North is likely to play in spades, possibly 6S. The best lead for East is a trump
Declarer will win, but must consider (a) trumps may split 3-1 and (b) he must not allow the opposition the chance to lead a second trump.
He needs 3 entries to hand, in order to ruff 3 diamonds in Dummy. The HA is one, and ruffing clubs must provide the other two.
Hence he will need to ruff high in hand at least once. So, he must win the first trick in Dummy, with the SA or S10, in order to protect his trump holding in hand.
After this analysis, and before playing another card, Declarer should plan the play:-
SA, DA, HA, diamond ruff, CA, CK, club ruff with the S5, diamond ruff, club ruff with SJ, diamond ruff with S10 (Dummy's last trump). Now a heart is given up, but SK & SQ win the last 2 tricks.
Note that if Declarer wins the first trick in hand, and if West can win the heart at trick 11 or trumps are 3-1, the defence will win one of the last 2 tricks, to defeat 6S.
The importance of planning before playing a card cannot be over emphasised.