I didn't do anything useful before I had to for work, and it took 10x as long as it should have. I'd suggest just taking some known working examples for fm radio, garage door openers, etc and working through them. It'll be painful, but with enough time and effort it'll happen. And it's sort of like makefile debugging-- the first ten times you have to do it it's excruciating, but after that it turns into just another task you know how to do.