Install Kiddoware's Kids Place - Parental Control.
Configure a 4 digit PIN that you will need to exit Kids Plae app and adjust Parental Control settings.
Choose the apps that you want your kids to use. These app will appear on Kids Place launcher screen and that's all your kids will be able to see.
Set up home button lock from Kids Place settings.
Lastly, just launch Kids Place and give it your phone or tablet to the kids. It will sandbox kid to a secure area.