Although the best policy after flopping a big hand is usually to bet it strongly, sometimes a hand can be so powerful that you might want to "slow-play" it and lay a trap to lull opponents into a false sense of security.
This approach is tricky and can often backfire, so there are several factors you need to take into consideration.
Is your hand strong enough?
If you opt to slow-play, you are going to give your opponents an opportunity to see more community cards without much investment. It follows that you need to make sure that those free cards will not improve your opponent's hand enough to beat yours. If the board is dry and you have a monster, a slow-play might work. But it is inadvisable to slow-play on a draw-heavy board.
Will your opponent fold if you bet/raise?
It is only really worth slow-playing if you fear any aggression from you will scare an opponent out of the pot. If you think their hand is strong enough to call a bet, or if they are already pot-committed, then there is very little sense in slow-playing. A slow-play is designed to get money into a pot that otherwise would not have been wagered. But if it is going in anyway, then a slow-play is not necessary.
Will it work?
You must be sure that a slow-play will be worthwhile. You need to know that an opponent is most likely to bet if they make some kind of playable hand themselves. Laying a trap against a passive player is almost always a waste of time. They will refuse to spring the trap.
Slow playing is risky and a tactic that many beginners employ inappropriately. The tutorial video talks you through some key elements of slow-playing a hand.