Instructions
Navigate to the Facebook website and log in to your account. Click the "Dungeon Overlord" link on the left of the page under the "Apps" section to start the game.
Click the "Get Dungeon Marks" button situated on the top right-hand corner of the game screen. Click the radio button next to the amount of Dungeon Marks that you want to purchase. A set of 25 tiles costs 30 marks.
Click the "Pay with Facebook" button and then click the radio button next to your payment method of choice. Click "Continue" to finalize your transaction. The Dungeon Marks will be added to your account.
Return to the game and click the "Shop" button situated on the upper right-hand side of the screen. Click the drop-down menu on the top left-hand corner of the shop screen and select "Rooms" from the list.
Click the "Buy" button next to "Extra Room Tiles." Click "Yes" to confirm your purchase and get more tiles for building rooms in your dungeon.