Complex sentence: He is at his best when he gets to push the ball forward on a fast break and mostly makes the right decision on the fast break, whether it means giving up the ball or taking it to the rack by himself.
Split into simpler sentences: He is at his best when gets to push the ball forward on a fast break and mostly makes the right decission on the fast brake. Wheter it means giving up the ball or taking it to the rack by himself.