The first thing is to decide if you want to follow the traditional route to being a published author, or if you will become a self-publisher, more commonly know these days as an indie publisher. If traditional I can't really help you as I didn't explore that avenue. I have followed the indie path and will be happy to share my experiences and, hopefully, you can learn from my, numerous, mistakes.
I also recommend that you sign up to KDP - the Kindle Direct Publishing platform. They have loads of advice and talk you through the process from start to finish.
In subsequent posts I'll be looking at cover images, formatting for e-book and paperbacks, using Create Space to provide print-on-demand quality paperbacks and all the other related matters such as obtaining ISBNs, creating a publishing identity and getting the right professionals in place to polish your output.
Then there is the marketing of the book - and that is a whole other chapter!