If was enabled, go to iCloud.com/find on another device.
If you're locked out because of a forgotten passcode, the only official way back in is to the device. This will erase all data unless you have a backup. Using a Computer (Recovery Mode) : Turn off your iPhone 5. how to unlock iphone 5
Keep holding the Home button until you see the (a computer and cable icon). If was enabled, go to iCloud
Watch this step-by-step guide on how to enter recovery mode to unlock a disabled iPhone 5: If was enabled