With Wrath of Ashardalon, not every tile is play-ready for adventure. There are 18 you have to set aside never to mix with the others unless instructed to do so. Feel free to sift through page 4 of your rulebook or take a look here.
Horrid Chamber tiles
(1) Large Horrid Chamber
(1) Horrid Chamber Entrance
(1) Horrid Chamber (start tile)
(4) Horrid Chamber
Dire Chamber tiles
(1) Large Dire Chamber
(1) Dire Chamber Entrance
(1) Dire Chamber (start tile)
(4) Horrid Chamber
In addition,
(1) Ancient Battlefield
(1) Vault
(1) Secure Exit
(1) Tunnel Exit
As far as the cards and the smaller components, take heed to the game-maker’s advice.
We recommend that you store these pieces in a plastic bag to keep them separate until you need them.