Complex sentence: After completing 30 matchdays, the top ranked team would be promoted to Liga ASOBAL, and each subsequently ranked team (2nd, 3rd, 4th and 5th) would compete in the promotion playoff for the one open spot in the Liga ASOBAL.
Split into simpler sentences: After completing 30 matchdays, top team is promoted to Liga ASOBAL, while teams qualified 2nd, 3rd, 4th and 5th play the promotion playoff. Teams in 2nd, 3rd, 4th and 5th place play the promotion playoff for a single spot in Liga ASOBAL.