You can have a start by looking at some of the video's from the Phil's Lab youtube channel. Apparently that is part of the same fedevel company. If you like the content / style and want more, then paying for the course might be worth it.
It's hard these days to make money with courses. There is so much stuff freely available that a course has to be good, thorough and compact to be worth it.
One of the "must watch" video's is the two hour long talk about GND planes by Rick Hartley. It's worth watching all 2 hours and 19 minutes at least twice (with a few months in between).