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.

Garry's Mod has entered the Guiness World Records: Gamer's Edition 2025 as the best-selling PC exclusive of all-time.

Garry’s Mod, the sandbox puppetry tool which teased the potential out of the Source engine circa Half-Life 2 and made it pull silly faces, has made its creators $22 million since the release of ...

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.

Source code playground Garry's Mod has raked in $22 million in seven years, creator Garry Newman has revealed.