Electric guitar...

A lot of times people teach too much and overwhelm the student most pop and rock songs are base on a few basic chords and keys, Learn the Major chords C A G E D and minor chords am em dm, learn them in open position aka cowboy chords learn to be able to do clean chord changes from one another, after that how to emblishish them, then how to play them in a few different places on the neck "moveable chords" learn em am pentatonic scales, people have done whole music careers off as much.
After that there's a few other chords and keys but not many for pop rock.

And if you learn some music theory remember most you will hear about is base on classical music and even though can be useful has little to do with pop rock, pop rock is based on blues and breaking with norms, It's mainly playing minor over major.