Help with a download

I downloaded the Starship Troopers model download from the garrysmod website.
However whenever i tried to use the models they showed up as ERROR. Big red ERRORS of Chaotic doom!

It’s a virus.

You know im kidding about the errors of doom right?
It says ERROR if you dont have the right model, material, texture, or anything like that.

make sure you add it to the addons folder should say <NAME OF ADDON NOT GARRYSMOD> in addons, if it still does not work, it’s broken.