Daisy leads the

6 and Mickey plays low.
Donald should play the

Q -
third hand high.
Minnie can win the

A but now Daisy's

K-J are high.
If Donald plays the

8 or

9 instead of the

Q,
then Minnie will be able to win an undeserved trick with the

10.
While third hand high is a good advice, you still need to use common sense. Here, Daisy leads the

Q
and next hand plays the

3.
It makes no sense for Donald to play the

K; he would only be beating partner's queen.
In the
next tutorial you will learn what to do when your opponent leads and you are second to play.