was just thinking what happens with the search cards if you do have more tokens on the board and less cards in the staple.

what happens with the "X" card (no treasure) and the chest card once they are drawn. are they going back to the other cards in the staple afterwards?

and if you do one quest and finish it what happens to the potions? can you hold it or are they going back?

During a "campaign" there are multiple "quest". During a "quest" there are, usually two, "encounters". During a "quest (both encounters) you only cycle through the searchcard stack one time. If the stack is empty you can't draw any more searchcards for the remaider of that "quest". After every "quest" (both encounters), all the searchcards are put back in the searchcard stack.

so this means ever potion also will go back at the stack?

As can be read in the "Rules of Play" page 20, chapter "The Campaign Phase". It states:

" 1. Receive Gold from Search Cards: Record the total gold value of every Search card the heroes acquired over the course of this quest on the CAmpaign sheet (even if the Search card was used during the quest). Then return all Search cards to the deck (even if the heroes didn't use their abilities). The heroes are assumed to sell their newly discovered treasures in Arhynn."

So every search card.

thank you very much