Confused Beginner.

I am a very "black and white" thinker. This can be good and bad. I like everything to be precise and many of my previous employments demanded accuracy so they did not help me to see shades of grey ( American - gray).

I have seen a video in which a gentleman says that if one frets at position one on the melody and bass strings an A chord is the result. I can see that the other chords are all what he says they are and he is an excellent player so he knows what he is talking about. 

What am I failing to see, please ? Why is an "E", an "A" and another "E" an A chord, please ? This A chord is not listed on the "Dulcimer Chord Chart" (Mel Bay) that has just dropped through my letter box.

I should have said that this is a dulcimer in DAD tuning.

Thanks.