Not flaming, but I don't get your question. What I think you are looking for is:

When you play a three chord song in the key of D you are playing D as the first chord, G as the 4th chord, and A as the fifth chord.

If you play the same song with your capo on the second fret, a C configuration becomes your first chord, an F configuration becomes your 4th chord, and a G configuration becomes your 5th chord, but you are still playing in the key of D.

This is called transposing.

If you put the capo on second fret and use the same chord configurations (D,G,A) you are now actually playing in the key of E.

learning how to transpose chords requires a capo and knowing how to count.