After most searching i found out how to access other textures to use with my TF2 map, yet they are all coming out purple/black chequered pattern instead of the texture they were meant to be. So I've look in a few other places, but being still pretty new to this editing stuff i still cant get the texture right and was hoping for a idiots guide to fixing this problem.

P.S the textures were from SiN:Episodes so i could get office textures.