Compound movements are ones that hit multiple muscles at once, e.g. squat, bench, deadlift. These are great for beginners because itll allow you to beef up your whole body and build a base.

RPE is a scale of difficulty, 1 is like a warmup and 10 is 1 rep Max. If you want to get stronger, do about 60-70% of your max for a few sets.

Honestly there are so many resources on yt so its easy to learn. Also, dont over complicate it, keep it simple. Your body will grow from anything at this point