bxa8=Q

if any of your pawns gets to the last row, then it gets promoted to a piece of your choice (knight, bishop, rook, queen). simple as that. standard rules of chess.

Since you mention auto-promotion, I would guess you're playing Live Chess? If so, then there is a box under the settings tab for Live Chess, allowing you to auto-promote, or not, depending. I hope that helps!

                                      Dc1985

EDIT: I just checked that game, and this link ought to be helpful.

http://en.wikipedia.org/wiki/Promotion_(chess)

I am asking about promoting a bishop to a queen or any other pieces like a knight or a rook?  See move 10 in game 

move 10. It was a pawn. Quick, go check.

The b means "b file pawn" not "bishop".

You are correct.  My apology to all.  Thanks for the help.