Ok... So I'm not sure if I can be much help here because I'm not quite sure what you mean by "not working". What do you see when you click on "Add a page"? Because you should just be able to just type whatever in the white space and add a page title and everything? Perhaps post a screenshot or something?

So, I'm trying to create a lay out where I can have several different pages inside my tumblr but I don't want the links to take me outside the blog. I want something like this. When you click on the link it'll take you a page that's still inside the tumblr. I see an option for "add page" and I keep trying to use that but it isn't working. Please someone explain this to me. I think it has something to do with tags. Also, I think this is the most confusing question I've ever ask. Sorry.