How can i create a map?

Hi everybody! i was wondering if there is a tutorial or something to build my own map?, i wanna create something like that episode of the simpsons where Homer enters into the 3d dimension...

for most maps you will need the map builder which hasn't been released yet.
however if you want to make a map from the 3d dimension you could easily download the flat map from the sharmp website and retexture it.