Chords for 2 guitars

Would you please help me on getting information on building chords for two guitars?

You will have to build the chords you self, but remember that if one guitar is playing a note, the other guitar does not have to.

Thanks. But i am still confused.
Let us say that one guitar plays the power chord like A.
According to armonic rules, What note should be playing the other one.
for instance a Asus4

a D.