Get thee to Amazon or your local bookstore or library and pick up a copy of The Copyright Handbook (Nolo Press) and read it with a highlighter handy (not the library book, obviously

. When it comes to copyright, every writer needs to know the law.
http://amzn.to/2AnPsVeMy .02: as a child psychologist, I'm guessing you spent your educational and professional life in a field with defined steps and process. Take this course, do that workshop, keep up X number continuing education hours, achieve that certification by a specific date, and so on. My daughter is a brand new MD and we've often talked about how her life since high school has been a seemingly endless path of specific steps.
Self-publishing is about as far from a defined path as you could find. I'm guessing the lack of defined, specific, digestible information about what to do, when to do it, why to do it, is driving you a bit batty. Welcome to this world.

1. Give yourself a break. All this stuff is new. Even the way you'll proceed -- no matter how you proceed--will be different from your previous career.
2. Find a way to give yourself the time you need to learn, which will be unique, depending on your circumstances.
3. Step one in the learning process is learning how to sift, filter and evaluate your sources. Perhaps you've written a rubric or criteria or two in your career? Write one now based on where you are and keep updating it as you learn.
4. All this stuff is figureoutable.
Best of luck! Sounds like you've made a stellar start