Thats the first question. Next who are the main characters followed by minor ones. Next how would the beginning start followed by the ending. Once you know how you want the ending to be look at the beginning. Example

Beginning: In a world where scientists create a being who has the ability to teleports from one location to another. How do they control him/her/it. Being escapes. Teleports into unknown location. Opens rift to where it moves around in time.

Ending. A boy who is able to teleport through time had created a place for others like him to live.

Next what are any of the twists and turns you want to use? Was it a hermaphrodite or a three eyed purple monster eater. Due to a change in history it finds himself nolonger a monster but a girl. Later finds herself as a boy. Finds he has ability to alter history so begins to change more and more history. Bla bla bla.

You fill in the blanks.

Characters: What type of people are you creating? What are their personalities and so on.

Are you writing a short story or novel? The shorter it is the less detail may be required. The larger it is the more detail. You have to decide as you work through the process. Overall you are the creator and have to set some guidelines else you could loose yourself in the plot and so on.

Well outlines depend on how far you've already plotted out the story in your mind. To write more into an outline or plot can make sense to see if the story works from the dramatics.

One of my greater outlines was for the story Werewoman - Sensate. That's pretty much the whole plot that I've decided before I even started writing.

SPOILER WARNING

Nerd, unemployed and unsuccessful with women is dragged to a party by some of his mates. He’d rather play a new computer game, watch an anime or read one of his favorite rule 34 fanfics.
His friends go dancing with some girls and he’s been left alone. He’s rather pissed and plans to go home; playing WoW is way more fun than this anyway. Suddenly beautiful women talks to him. He instantly likes her, but she dominates their conversation. She talks about politics, one of the few themes he can actually talk about.
Then she asks him if he wants to follow her home. He’s still a virgin and a bit shy. But she can convince him since he’s drunk and she tells him it’s better to follow her home. There they both cuddle on her couch and after feeding him some snacks she makes him really hot and asks if he wants to fuck her. He’s aroused enough that he accepts, but confesses that he’s a virgin. She grins and says she knows.
He loses his virginity and spends the night with her. The next morning she tells him to return in the evening. He goes home to play some further pc games, but doesn’t really the same satisfaction as usual. He can’t help himself thinking about her. In the evening he appears early and they talk about stuff. He tells her about his pitiful life. She doesn’t seem to be too worried though, amazing, especially since she seems to be rich. (No hypergamy)
When the darkness falls they’re watching a movie about werewolves. Suddenly his whole body convulses in pleasure he has an orgasm for five minutes and when he can think again he realizes he’s a girl.
Second personality kicks in and her body really feels right. She loves the feel of her boobs and her crotch. Alpha pulls her out of her reverie and shows her how to use makeup and polishes her nails. Alpha intends to figure out the dimensions of the second personality. She doesn’t complain once and draws in the new knowledge like a sponge-
She starts rubbing her legs together and squirms on her seat. Alpha asks what her problem is and she tells Alpha that she wants, no needs to be touched. Realization dawns Alpha, it’s a sensate. Alpha touches Sensate’s breast. Sensate starts an orgasm. They have sex afterwards until Alpha is exhausted. Sensate still wants more, so alpha gives her a dildo. Sensate dildoes herself until she drops unconscious.
The next day Sensate wakes up as a guy. He’s disgusted by the memories of last night. Being nothing but a sex-addicted slut. He realizes he still has nail polish on his hands and searches the bathroom for nail polish remover. Then he goes in the kitchen and realizes alpha is gone. Alpha has left a message, that Sensate is expected to be back in the evening.
Sensate runs away, planning to stay away forever. On his way home, Sensate wonders how nice it would be to suck the hot guy’s dick, which freaks him even more. When he returns home, he has no motivation to play his games at all. His normal ways to spend his time don’t satisfy him at all. Out of frustration he goes shopping for groceries. That doesn’t really make things better though. Even the fat guy at the checkout seems attractive. When he returns home, he tries jacking off, but that only makes him fantasize having his nonexistent boobies rubbed and being penetrated where he has no hole.
Although he fears what happened to him last night Sensate needs to return to Alpha’s home. He’s let in by a new woman. She looks like a goth. Goth leads her in the living room. A superbly beautiful woman is waiting there. Goth and Model tell Sensate what she is, Alpha forgot doing that yesterday. What type of werewomen they are and how being a werewoman works. Alpha returns, he’s a guy now. Sensate doesn’t really recognize him, but then she feels his presence. An older guy comes with Alpha. Alpha talks to Sensate and properly introduces him. Sensate tells Alpha his fears. Then Sensate changes, while the others talk about the problem a sensate poses. They’ve gotten nowhere, when Sensate has finished her transformation.
Sensate instantly craves sex. Still they need to discuss her situation, so they bind Sensate with their bondage gear, put a vibrator in her pussy and vibrating nipple clamps on her boobs. They also gag her, to muffle her lustful screams. Alpha and Goth realizes how distressed Sensate is about her Situation and Goth tries to calm her.
They conclude it would be best for her to work as a prostitute. Alpha has a friend who runs a good brothel. She’ll work night shifts and life her days with the harem at the Alpha’s mansion. Sensate thinks a steady supply of sex is a good idea, so she’ll take a job at the whorehouse while still draw social security.
Goth cares for her sexual needs. Once she’s able to think about something else than sex, Goth talks to her about her life. Sensate tells her what she did, and why she’s been such a social failure. Sensate is glad someone really cares for her. She’s actually interested in Goths problem too…
Model, Normal and Sensate will stay at Alpha’s mansion, while Goth has her own house. Goth wants to leave early, but Alpha’s orders her to stay and sleep in a guest room. Alpha, Model and Normal fuck Sensate. Alpha needs to rest too, since he also has to work, but Model and Normal fuck her the rest of the night until they all start to drop of exhaustion. Sensate crawls into Goth’s bed.
She wakes up way to early when Goth leaves. Sensate is male again as is Goth. He doesn’t look goth in his male form though. Sensate realizes that he’s in love with Goth. Goth dresses and when he wants to leave, Sensate stands up and gives him a kiss on his mouth. Goth responds and tells Sensate he loves him too.
Sensate goes back to bed and sleeps until afternoon. He eats and checks out the house. Goth returns, and changes into a her as soon as s/he’s at Alpha’s mansion. Goth asks Sensate to play play station, but Sensate doesn’t really enjoy it, which really distresses him. Goth decides to teach him about engineering since there is no reason why Sensate shouldn’t use his head for something else than to figure out a way to get herself penetrated.
The main difference between Sensate male and female version is his/her attitude on gender and the need to have sex. While the male version is disgusted of himself, the female version loves her new addiction.
Alpha returns and turns Sensate into a female. Then they fuck. Sensate start’s her job as a prostitute, while the rest of the harem establishes their connections.

END SPOILER

I wrote far less for the first chapter of Jan's tale. While I had written down some information about the characters, the outline/plot for the > 10000 word chapter was only two paragraphs.

SPOILER WARNING

Plot: Protagonist is on the train. Muses about the way he got to Whateley. Leaves train and muses about reflection in the mirror. Decides to talk to students, but they talk really fast in his opinion. Not that good in english. Girl talks to him (happy TG) and asks about his progress. Wants to suggest dresses and makeup. Thinks his current stuff doesn’t fit so well.

That pisses him off and he leaves. Reads a book in his corner as he doesn’t want to intrude on conversations. Leaves with bus and listens in on conversations. Ayla introduces himself and they tell their stories. Protagonist feels bad about going off at the girl like that. Ayla leads the group around. Protagonist ends up in room with his “enemy.”

END SPOILER

It obviously doesn't make much sense to outline chapters in the beginning. That'll only hinder you in your creative writing process. You'll probably change that anyway. One chapter may become three and four planned chapters may just get discarded or shrunk down into one.

I think two different flavors of outline would help you. One is an ideas outline - the other is a plot outline.

The ideas outline is almost the harder in many ways... So I'll get to it second.

A plot outline is fairly simple in concept. How far a person takes it is up to them. The basic idea is you make a heading for each major "event" in your story (Chapters or sections that contain chapters, eventually) in the order they should happen in the story. Then, you make sub headings for minor events along the way... And keep doing this until you've got enough to write (& keep things straight as to what happens when). As you go, don't hesitate to add "body text" where you might write about what's going to happen there... I've known some people who keep writing in the outline mode and end up with all, or most of the story written as they wrote to fill in the spaces in the outline. (I don't go to this level for most of the story, though a time or two I HAVE written stuff in the outline that I took "as is" and put into the story.

The ideas outline is a place where you can organize the ideas you THINK belong in the story. They can be challenges to be overcome. They can be puns you want to work in. They can be historical figures or events you want to reference. They can even be people you know that you want to "honor" in some way. They can be character sketches of someone who should be in the story. The list of what goes here can be almost endless. Once you get a few of them jotted down, you can start to "categorize" and "organize" them... My experience here is that unless you've an outline from a previous story, you end up building this from the leaves to the roots (i.e. backwards).

Hope the ideas help you.
Annette