Trouble getting setup

I want to use this for the following website: We have a Facebook page at

I installed the plugin on our test environment, so I can learn to use it before pushing it live. Our test site is There is no Facebook account that ties to that.

At any rate, I am stuck at square one and can't get the Facebook API set up. I have tried to follow the steps, but can't get the first step done! The first step is "create your application" and it says "look for Site URL field in the Web site tab." After I click on the link provided, I don't see any such tab anywhere. Please see screenshot attached. I'm sure I'm missing something obvious.