The other tabs are automatically hidden until you begin to enter information on the Summary tab. Read through the Guide to Getting Started, to help get you started.
[A quick note on this topic a few months after answering this question: I’ve received this question numerous times since first releasing the model, and it makes sense that many are confused about this issue. The model includes dozens of tabs (and growing!), and so to improve user experience I’ve added functionality to automatically hide/show tabs depending on the specifics of the deal you’re modeling. The idea is you only have tabs open that you need. When you first open the model, you only need the Versions tab and the Summary tab. As you begin to fill out the Summary tab, the tabs you need to complete your analysis become available to you.]
