Decide where to publish (i.e. Amazon KDP, Apple Books, Barnes & Noble Press, etc.)
Check out Reedsy Discovery to get book reviews after publishing
Upload book through EPUB to have it formatted before submitting the book to Amazon or any other platform.
Participate in the “search inside this book” program on amazon
Use Amazon KDP
Use GoodReads after publishing: https://www.goodreads.com/author/program
Add a disclaimer to the book about violence and suicide as well as look at how and what to include in a disclaimer. Since it is fiction the characters and situations are not tied to any person or event.
Look at this book promotions site options: https://blog.reedsy.com/book-promotion-services/
Make a book trailer
Write a Sequel in the meantime
The list will go on and on as the publishing time gets close