If you’ve moved to iOS 12 beta and want to go back here’s how to do that on iOS 11.
- Turn off your iPhone X (hold down power and volume up for a few seconds)
- You’ll need a Mac so fire up iTunes
- Grab your lightning cable
- Plug it into your iPhone whilst holding down power (right side button) and volume down at the same time
- Click restore
Once your Mac has downloaded iOS 11.4 it’ll start to restore your iPhone.