I have prepared a (free) short course called Thinking through Self-Publishing. Lifelong Dream. There is a second course (Writing and Publishing When time is Scarce) on the same site with lots of practical how-to info on writing, publishing, andmarketing ($29). However, you can learn what you need by studying free info at the sites. You can also go to this blog index, where you will see lots of how-to articles. All those are free!
Sometimes it will seem like a lot of info to absorb, but you can do it. If you get frustrated, take a break and come back to it.
One final point. You only get one chance to make a first impression. Do not publish the first draft of your book! Put it in a drawer and come back to it a bit later so you can be a cold reader. Ask others for comments, but do remember, all choices are yours. If you can, pay for an editor.