: Use Left Click to grab and move objects. Right Click freezes them in place, and holding E while moving the mouse allows you to rotate the object.

: You can save your creations or download "Duplicates" (Dupes) made by other players through the Steam Workshop. Multiplayer and Add-ons

Getting comfortable with the basic keybindings is the first step to mastering the sandbox:

The core of GMod is building. You can start by spawning basic props and "welding" them together using the to create cars, rockets, or even complex robots.

: Use the Undo (Z) key to quickly remove the last item you spawned.

: This is used for advanced building (e.g., welding, creating thrusters). Select a tool from the right-hand side of the Spawn Menu, then Left Click on objects to apply it.

While the single-player sandbox is great for learning, the game truly shines in multiplayer and with community mods: Guide :: Gmod: How to have fun - Steam Community