Plug the Yellow Plug directly into a wall outlet that you've tested to make sure it's wired correctly. Strip the #12 Green Stranded Wire and put it in the Ground Lug.
Don't plug this into a power strip! You want the best ground you can get, and you don't want to include all the extra (smaller) wire in a power strip.
Always use an Outlet Tester to make sure the outlet is wired correctly, and that there's a ground.
For more information on proper grounding, see our Electrical Grounding Tech Bulletin.