iPhone app stuck after multitasking

Hello,

I am experiencing a problem after I have built my game in Xcode and is successfully running on my iPhone 4S, iOS 6.1.3. When I go to the homescreen and close my app in the multitask bar, the game does not reopen correctly; it's stuck on the loading screen. What I want, is:

• When a user presses the home button in-game so he leaves my app, the app should resume activity when it is called again in the multitask bar

• When a user double taps the home button, my game should resume its activities. In this scenario:

1. If he chooses to switch apps, whenever he switches back, my game should resume its activities

2. If he chooses to double tap again so he ends back up in the app, the game should resume its activities

• Whenever my app is closed in the multitaskbar and then reopened any time later, the app should start

Could anyone please help me with this? Thanks a lot!