No worries, Christine - We'll try to help out as best as we can, knowing that you'll probably be relying quite heavily on the Community.
Once the munchkin code is on the page, you need to physically visit the page (or someone does, so that the page URL can be indexed by Marketo (just like Google does)). Once indexed, that page URL will appear as one of the values in the "web page is" constraint (where you're currently seeing the red squiggly).