Thanks for stopping by the Apple Support Communities. I understand that you'd like to restore an iOS device from an iCloud backup. I'm happy to help!
Instructions on restoring an iCloud backup, and other data, from iCloud can be found here: iCloud: Restore or set up iOS devices from iCloud. Restoring a backup removes any information currently on your device, replacing it with only the information that was on the device at the time of the backup. If you have information currently on the device you want to keep, I recommend before restoring a backup that you create a current one: How to back up your iPhone, iPad, and iPod touch - Apple Support.