I'm not too sure what you're asking but I'll give it a shot. You can turn on iCloud by going to Settings, iCloud. If you already have an icloud account(email) enter the email and password. If you don't tap new account and follow the steps to create an iCloud account. Once the account is created all the options should be turned on for the device. If you have any other iOS devices or on a Mac you will need to enable iCloud on those as well with the same account. When you create, edit or delete contacts on any of the devices with iCloud enabled it will update the contacts on all of the other devices automatically.
Backup
Once your iCloud account is created and logged in scroll to the bottom. Tap Storage & Backup, make sure iCloud Backup is toggled on. Then you can either let it do the backup automatically or you can manually do the first backup by tapping "Backup Now". In order to do a backup your device will need to be connected to a Wifi network.