That is not a vary usful lesson, to which bass chords are not often used. However when playing songs like mother-danzig, kryptonite-3 doors down, teens spirit-nirvana,. they can be quite usful and give quite good effects. Bass chords are best suited to songs that give a quick punch of sound, with the bass riffs being the root note of the guitar chords (eg: Em chord>E note on bass).
Bass chords should be played on the D & G string becuase you get a hight pitch tone out of them. If you play them on E & A string they will sound very muddy, and ugly. However you can make little exceptions for chords like Am.
These are just basic chords. They are the most common one and best to use on a bass. Chords like sus,9th,7th etc do not sound good. That is why I have only written these main chords.