How can I make sure my children will not do something they should not on my phone?

This FAQ applies to Nokia Lumia phones with Windows Phone 8.

You can create a safe and fun start screen for your kids, so that they can play with your phone without, for example, accidentally deleting your work mail or making online purchases. Put selected apps, games, and other favourites for your children to enjoy in their own start screen.

On the start screen, swipe left, tap Settings > kid’s corner, and select which content your kids can use. You can also set a password to keep your kids from accessing your own start screen.

To go to your own start screen, press the power key twice, and swipe up on your own lock screen. If you've set a password, type it in.

To go back to the kid's start screen, on your own lock screen, swipe left, and on the kid's lock screen, swipe up.

To switch the kid's start screen off, on your start screen, swipe left, tap Settings, and switch kid’s corner to Off.