Click on piece you want to move, then click on the square you want to move it to. To unselect your piece, click it again. For some reason, if you select the computer to play White, the computer will play itself regardless of whether Black is selected or not.

CPU White
CPU Black

Promote to

Game Log

Castling, en-passent and pawn promotion are permitted, but the rule "Game is drawn if a position repeats three times" is not implemented.