Can't insert a Table of Contents

I'm trying to create a new document using one of Pages built in templates (Page Layout - Newsletters - Sailing Newsletter) and I can't seem to add a Table of Contents no matter what I do. It's just "grayed out" and wont let me do anything. Can someone please help? I've been using Pages for a while now, but this is my first real attempt at adding a table of contents. Any help is greatly appreciated.

Thanks,
Jesse