Can I just add that what you are calling simple chords as opposed to "full" chords are chords that have only one of each of the elements of the chord in it. Like one Root, one 3rd and one 5th (CEG). A "full" chord (open position C chord say) has 2 roots 2 thirds and 1 5th. Learning to hear the triads or simple chords makes learning voice-leading easier down the road, and allows you to be much more creative and musical as you become a better player. It requires you to know all of the notes on the fingerboard, but is you get into more sophisticated kinds of music it will be well worth it.