How would I do this?

[John Doe]

Hey guys,

I;m working on making a chess program and I hit a wall. I have no idea how to get the position of the chess pieces. I have the chess board 1-8 and A-H for black as well as 1-8 and a-h for white. i just have to figure out how to declare those positions for the actual pieces so like the row of pawns for black would be B1-B8 as well as be able to replace the other coordinates with the piece when they move there like if I moved a black pawn from B1 to C1 B1 would be empty and then C1 would have it. 

I'm sorry if that's confusing but I can't seem to figure out how to do it... Any help is greatly appreciated and thank you in advance!