Help with addons.

So I’ve been trying different addons for a while and I find that almost none of them work. Some do, most don’t. In particular I’ve been tring to get this addon:

I know how to get to the garrysmod directory where everything is, but I’m not sure how the addons work. Is there something I’m missing? What I’m really asking for is more exact instructions then just: “Put it in the directory.” Help?

you could get Kermite’s shotgun pack. it includes that gun and several others that are fun to screw around with.

Put the folder with info.txt in garrysmod/addons
So if I had military model pack I would put it in:
C:\program files (x86)\Steam\steamapps*\garrysmod\garrysmod\addons
So I would have:
C:\program files (x86)\Steam\steamapps*