The numbers on this one indicate places you can put important details or encounters--the blue ones indicate exterior encounters, everything else is inside the buildings.
You can treat the interiors as cutaway views or as interiors of intact buildings. The positions of interior doors and stairs are usually implied, so only a little imagination and notation should be required.
In this one, identical colors near each other indicate connecting interiors. The goblins can be goblins or whatever else...
This one is a d100 table for any kind of big dungeon or encounter area for a party around level 8-12. You write in the boss on the top and the cannon fodder on the bottom, the pink is just suggestions for the kind of creature to put in there.
You can just key the dungeon 1-100 or roll randomly for each room. The hit dice of the creatures is written down the left side.