For a dungeon adventure you need a good-sized map or room layout. I found some great generic maps in the Map-a-Week archive at the Wizards of the Coast website. Below is an example.

When a numbered area is reached, reference whether it is a "Room" or a "Common Area" on the key and use the appropriate room contents table. If you come to a door, use a door type table. Treat all non-numbered areas as empty areas or rooms with broken, deteriorating walls and doors.