Urgently need your help. What´s the meaning?

[bob jenkins]

Re-Pick: Player A1 screens the opponent. When the opponent runs past the screen, the offense changes direction and the same player re-screens the same opponent.

Down: I'm just guessing here, but that might be the name of the play that's being run. So, the phrase, "whenver we have a down" might be translated as "Whenever we run the play called 'down' (or containing the word 'down') it's a pick-and-roll."