no "data" folder on gmod folder?

hey guys… i recently install gmod… when i’m looking for the data folder, there’s no Data folder and addon folder… help please

Create them

but i need to create the adv_duplicator too right?

Why would you need a data folder? You don’t need to make one if you install adv_duplicator it will be made automatically.

Installing Adv.Duplicator and launching the game, going into singleplayer, and saving a test contraption with it at the most is what you have to do. It should be just starting the game and loading singleplayer.