Today's video covers two important topics: one is the Fourth Suit Forcing convention and the other is the simple squeeze. A bid of the fourth suit in an unobstructed auction doesn't promise cards in that suit--instead, it is an artificial and forcing bid that asks partner for more information about his hand. This is an intermediate/advanced convention that comes in handy when you want to force partner to game but aren't sure about what strain to play in yet. Partner responds by bidding secondary support for your major suit, or making another natural bid to describe his hand.
Later, as declarer, Graeme explains how a fancy play forces one of his opponents to discard his winning cards. The play executed here is called a simple squeeze, and it's a rather advanced play. But the principle demonstrated applies to players of all levels: often times, cashing your high tricks and delaying a finesse is a winning strategy.
After watching the video, try playing the hand.