i'm not sure where you find them before game time and i wouldn't know how you'd find the umpire for the first game in a series, but for the second game and so on they rotate around the bases. so the ump on first will be behind the plate on the next game while the second base ump will be on first and the third base ump will be on second. so it rotates clockwise. there probably is a place you can find this information before a game but i'm not sure where
