How to reactivate a phone after it’s been erased

This should be as simple as inserting an active SIM card and then inputting the Apple ID when asked for an Apple ID and Password for activation. If your iPhone had been erased then it should be at the "Hello" screen and you can advance from there.

Axel F.

What happens when you turn it on? See if this helps: https://support.apple.com/en-us/HT201407