When you defeat a regular Event, flip that card over and add it to your Collection. During any Event game, the Heroes have a number of Collections they can bring into that Event, indicated by the front of the Event card.

You must choose which Collections you bring with you into an Event game before the game begins, though each Collection provides two different rewards. One of the two rewards listed on the back of the Event card can be activated once per game at any time during a Hero’s turn, though not in the middle of other actions.

So, you can use a Collection reward before or after playing a card or using a power, but not while a card, power, or other effect is still in the process of resolving. After a Collection reward has been used, remove that card from the game. It’s still in your Collection and can be used in a future Event game, but it’s expended for the rest of this game.