That's cleared up, let's address the 'how'. You'll need Garry's Mod 13, the current beta that Garry's been developing for the last year. If you have GMod on Steam you'll now have access to the beta.

Official Garry's Mod spiritual sequel Sandbox is finally available for everyone to try, letting you make any game mode you can think of.

Source Engine-powered Garry's Mod is a robust physics sandbox, commonly used for putting silly faces on familiar Half-Life characters. And on Thursday, there will be a new way of interacting with it: ...

The Garry's Mod PC utility has earned creator Garry Newman $22 million in seven years, as revealed in a recent developer mailbag. Newman noted that the team got "less than half of that though. Then ...