NEW YORK — The Nets don’t have time to mess around, but that’s the position they find themselves in. With 18 games left in the season, the early-season championship favorites still have no clue what works for this roster that’s been constructed on the fly. “I think we’re getting there,” said interim head coach Jacque Vaughn, who is expected to return to the bench if Steve Nash clears the health and safety protocols in time for Sunday afternoon’s matchup in Boston against the Celtics. “It’s looked different at different times of the year.” The Nets have to take advantage of the few remaining ga…