How do I add downloaded creations to Gmod?

I just got the game and am very new to it. I need to know where to put downloaded creations at in order for them to be usable in gmod. I know how to add mods and guns, but I don’t know how to add saved creations.

This is the creation I want to add for example:

It’s an advanced duplicator file. You’ll need to download the advanced duplicator tool, and put the ‘creation’ file under /garrysmod/data/Adv_Dupe/ then you can go into garry’s mod and use the Advanced Duplicator tool to paste the ‘creation’.

Addons:
garrysmod/garrysmod/addons/

Maps:
garrysmod/garrysmod/maps

Adv dupes:
garrysmod/garrysmod/data/Adv duplicator

Thanks!

[editline]11:13AM[/editline]

I looked around online for the advance duplicator but I came up with multiple possibilities… any chance you could link me to the best one?

http://www.facepunch.com/showthread.php?t=688324