This deal was (mis)played in an EBU online duplicate.
With no attractive lead West tried the spade jack against three notrump. This was covered by the queen, king and ace.
Declarer now played the eight of clubs to the jack, a club back to the ace and then a heart which West won with the king.
The six of spades was mysteriously ducked by North, not that it mattered, so West got off lead with a diamond to the ace, six and five.
Dummy now cashed the king of clubs, the ten of spades and then the seven of clubs, with East discarding a spade and a heart and West two diamonds.
This was now the position.
Now declarer played a heart to the ace and the ten of hearts. West did not cover, but declarer was able to exit with a diamond to West to get to his heart winner.
There were a number of errors here, East should keep another heart so as not to give away the heart position. West should have discarded the king of diamonds and kept a small one. Declarer could have made the overtrick in various ways; by not cashing the last club so that he had a late entry to dummy or by unblocking the ten of hearts on the first round of hearts.