Instructions
Turn on your PS3. Insert "Call of Duty: Modern Warfare 2" into the optical drive. Allow the game to boot. If it doesn't automatically boot, scroll to "Game" in the PS menu. Select "Call of Duty: Modern Warfare 2" and press "X."
Go to "Multiplayer." Press "X" on "Local Split Screen."
Select the map. Then select the rules for the match. Press "Start" to begin the match. You can now freely run around and observe the map. If you wish to play against an opponent, you will need a second controller in this mode.