Accidentally emptied folders + addons won't work

I have two problems… First off, i accidentally emptied some content folders in the Q menu. How do i get the stuff back?

Second off, when i try to download some models, they will never show up in the game. I did extract everything to the Addons folder with Winrar, and it does have the info.txt, so how do i get it to show up in the game?

Help me

Don’t always assume that content goes on addons. Don’t bumb after 20 hours, and just reinstall gmod, deleting the folder completely if you have to.