Iain Rob Wright, a fellow horror author and friend of mine is running a course at the moment for self-publishing.
This guy really knows his shit, so if you want to know what works and doesn’t in terms of selling books then I would heartily recommend this course.
I have had a quick look at it and the information contained is very comprehensive.
Take a look here: https://azofselfpublishing.com/?ref=14&campaign=A-Z self-publishing
rayneofterror1.com 