Ultimate Facebook

In the instructions to set this plugin up in my blog, I'm encountering issues.
Here are the instructions I was given:
To do so, follow these steps:

Create your application
Look for Site URL field in the Web Site tab and enter your site URL in this field: http://stephaniedeni.com
After this, go to the Facebook Application List page and select your newly created application
Copy the values from these fields: App ID/API key, and Application Secret, and enter them here:
Once you're done with that, please click the "Save changes" button below before proceeding onto other steps.

When I attempt to locate the SITE URL field, I cannot find it...ANYWHERE.
Can you please help me out?

Thanks,
stephanie