how to mod maps?

how do i mod a map? Like just a wall.

If you wanna change the textures of walls, you need textures.rez

If u wanna mod how the wall looks, mod the textures like said above

If u wanna make a custom map...don't, its possible but not worth the time it takes to make it

If u wanna edit for premade maps like snow valley, don't. The game can detect the modded map

thats called wallhack lmao