The tile is almost exactly like the original gmod, but you should add more space to the map, to build houses and use the gmod commands. Also, if you can, try to found the background or take a screenshot in gmod of the background of the map and put it on the map as background.
Tutorial: 'How to make map for Gmod'
Step 1: Choose good tileset like 'cs2dnorm', then set map size (it must be big)
Step 2: Add grass as ground, then make wall outline arround the map.
Congratz! It's ready to play!