Addons don't woek

I am having trouble with my phx3 file because i got garrysmod of steam, and people keep telling me to put it into the Addons folder but there is none, i need help please

Have you run Garry’s Mod yet?

yes lots of times, the game works fine, i managed to get the gooniverse on their, other than that i cant get phx3 or mining to work

Create a addons folder.

i tried that, and i also tried reinstalling it to see i fit was a fault

So, is there an addons file when there is this:
That’s what it should look like

Then MAKE one!