title: How to add a screen to my game in WP7 XNA?
body: <p>I've just finished a game in WP7 XNA, I need now to make a main menu screen, highest scores screen, and instructions screen.</p>
  
  <p>I need to know how to add a screen for the main menu, and how to make the game start executing from there.</p>
  
  <p>And how to navigate between these screens.</p>
  
  <p>Thanks.</p>