we all about fullbright here

HOW DO I USE THIS?
Go into the "all_the_things" folder, then into the "maps" folder in it, and you'll see four .bsp files. Drag one to or copy and paste one in your game's "maps" folder. You could also do ALL OF THEM FOR MAXIMUM SPIDERS

WHERE DOES IT GO?
Your game's "maps" folder? Follow the path below, it's basically in the same folder as your "custom" folder.
Program Files (x86) > Steam > steamapps > common > Team Fortress 2 > tf > maps

Do note, all the maps have a small amount of player spawns. Being only six total, three each for RED and BLU.