Take the South seat here, declaring four hearts on a trump lead. You try the queen from dummy, and that holds. Play on.
You may have a trump loser and a loser in each of the other suits. In that case, you had better set up the clubs for a spade discard. That will be easy enough if clubs are 3-2, but a 4-1 split could prove troublesome.
The original declarer tried a club to the ace at trick two, followed by a diamond. He intended to cut the defensive communications while eventually reentering dummy to lead through the potential club void on his right, but all it served to do was sacrifice a tempo. West won and accurately switched to spades. Declarer took that with the spade king and played another club, but East discarded. West won the third round of clubs, whereupon a spade continuation ended declarer’s chances. East overruffed the fourth round of clubs and cashed a spade.
Declarer’s timing was off. He did not actually need the heart ace as an entry. It would have been better to cash it at trick three and then lead a low club from hand. This preserves the club king as a reentry. If the defense switches to spades, declarer wins in dummy, leads a club toward the king and ruffs a club. The difference here is that South still has the spade ace to control the suit and can eventually discard dummy’s third spade on a club.