apple watch

I unpaired my apple watch series 3 from my Iphone and factory reset the watch before I sold it. It is not showing up in my Icloud account or on my phone but the new owner is having trouble getting it on her ICloud account. I had to factory reset it because it had me locked out for to many password attempts (it was bumping around in my purse), so it unpaired from my phone.

what do we need to do?