If you're a Page Admin of your dealership's page, you should be able to go to the actual APP'S PAGE then, under its logo on the top left, you should see an option that says "Add to Page".
That option might not be there IF YOU ALREADY HAVE ADDED IT (and just don't know)
Go into where you edit your page and scroll down and look for Static FBML under the applications. Once Static FBML is renamed, it will show whatever name it was given on the Tab (so, in my example, it would say My Inventory - FBML) The little icon for the app looks like a grey square box with two arrows inside of it pointing away from each other.
Check it out and see if it's there already, maybe someone added it once to use it for something else. Don't worry, if it's already there, you can add another one from within the existing app. Just click on "edit" for the FBML app and all the way on the bottom it will say "add another FBML box"