Trouble with downloaded maps

Hi! I’m very new to gmod, so excuse me if this is a total noob question.

I recently downloaded a new map (RP_EvoCity_v2d.bsp) and managed to add it just fine (pasted the extracted file into the maps directory). However, when I loaded the map up in GMod, there were big red error signs everywhere, and a bunch of texture seemed to be missing or replaced with pink-and-black checkerboard pattern. Have I missed a file somewhere along the line, or what’s up?

If it makes any difference, my other Source engine game is The Orange Box, with all component thereof installed.

Thanks in advance!

-snip-

It goes in addons

he probably needs to get phx or get counter-strike. im starting to see maps with phx props already in them.