Artistic Cyber-Skills

I am looking to publish another book on Amazon later this month which is a collection of my historical character based stories. Covers for my other books (https://www.amazon.com/gp/product/B093BH5CHM?ref_=dbs_p_pwh_...) are attractive images on theme, but for this next book I have been toying with a cover that will be a collage of some of the characters in the book. The problem is that I have no idea what I am doing, as my attempt below will show!
Can anybody help me do this?
Maryanne