How to add a screen to my game in WP7 XNA?
I've just finished a game in WP7 XNA, I need now to make a main menu screen, highest scores screen, and instructions screen.
I need to know how to add a screen for the main menu, and how to make the game start executing from there.
And how to navigate between these screens.
What you need is introduction to XNA best practices. I would recommend you checking out that sample http://create.msdn.com/en-US/education/catalog/sample/game_state_management
The sample helped me a lot with understanding how to manage screens, input and menus in my game.