dj's = double jumps?
After you read all those links I posted you will discover that the world you are making your map in is a big giant space.
You have +/-4096 units to work with in the X, Y, and Z axis (read to learn what those are).
You have to, by creating walls, floors, and ceiling/skies, have your "MAP" area enclosed and SEALED.
If during your compile you notice ***LEAKED*** in the compiler's console window, your map is NOT sealed.
You MUST also have all you entities INSIDE your sealed map. You can not have spawns, lights, guns, ammo, func_trains, water exposed inside the map, or anything else outside of your "SEALED" map area. Example: Look at the map Blitz. It's a sealed box. All other correctly built maps are sealed just like this, except some maps are much more complex.
DOUBLE JUMPS are not something you build according to a formula or directions. You jump, and while in the air to contact an edge of a brush and issue another jump. If done correctly you FLY LIKE THE WIND.
GO READ NOW