Plug-Ins folder location

Hi, I'm having a difficult time installing 3rd party plug-ins in Premiere.

I've read that premiere shares the Plug-ins folder with After Effects, yet when I download plug-ins and put them in that folder they do not work. I also created a new Plug-ins folder in Applications/Premiere/Plug-ins, and installed the plugins there but again, nothing.

Novice question, but what am I doing wrong?

Thank you.