MISSING TEXTURES TUTORIAL:
(IF YOU HAVE CSS, JUST SELECT THE GAME IN THE GAMES TAB)
Go to this link: http://kajar9.wixsite.com/cscheater2/downloads
Find the CSS tab and click MEGA Game Content.
After it finishes downloading, open the WinRAR file.
Make a folder called CSS Textures or something like that, doesn't matter.
Extract everything from the WinRAR file to the new folder you just made.
Copy the folder that we just made.
Go through your program files (x86) and find your steam directory.
Open the steam folder, go to steam apps, then common, and click Garry's Mod.
Click the second Garry's Mod folder and open add-ons.
Paste the CSS Textures folder from earlier into add-ons.
That's basically it if this confused you go to this video: https://www.youtube.com/watch?v=yaL7gISscEY
If something didn't work or I skipped a step, let me know.