What to do with the cards at the end of the scenario

My apologies if this has already been posted but, being new to the game it's hard to know what to search for.

At the beginning of the game you get to choose what cards go into your player deck. The rulebook gives you good cards to use, but you can use any as long as you're sticking to the number of each type. Does that end after the initial game? In other words, if you banish one of the cards you started with, do you just have to hope that you picked up some loot in the scenario or you just have to play with 14 cards in the next scenario?

Also, when you're finished with a scenario, do you put all of the cards from the locations back in the box to possibly encounter them in the next scenario?

Thanks guys.

You can use any boons you acquire during the scenario when you reconcile your deck to its card limits between scenarios. All of the group's cards, old and new, basically form the pool from which you must reconcile your decks. If you do not have enough cards of a particular type for everyone to form a complete deck, only then may you go to the box. If you have to go to the box, you must abide by the basic trait restriction until you begin deck 3, at which point the basic trait restriction is lifted and you can take any card that is at least two decks lower than the one you are currently playing. This also applies for starting a new character.

All other cards go to their proper stacks in the box.