Right or wrong, I refused to learn all this stuff.
I just went out and bought a Bushmaster, took it home, and started shooting.

A couple thousand rounds later, I know everything I need to know.

Oh, my plan was to sell the first rifle, and buy what I needed after the Bushmaster "taught" me what I needed to know.

I still shoot the Bushmaster, but, I did buy a second "cheapo" recently at a gunshow. $300.
It is a beater, but, I have had that one apart and back together dozens of times.
The beater shoots great,, looks terrible.
The beater came with a bunch of "extras, even a 22LR adapter.
I was amazed when the beater cycled with bulk 22LR ammo.

So, what I am saying is,, start enjoying, rather than studying,,
you will learn what you need to know along the way!!