Set up Apple Watch (renewed) 7.
How do I set up my renewed Apple Watch 7?
Question marked as
Not quite sure what you mean by Renewed unless the seller described a pre-used Watch that way, in which case it hopefully just means cleaned up.
Set up your Apple Watch as follows...
Set up your Apple Watch – Apple Support (UK)
which includes this article how to set up cellular
Set up mobile on Apple Watch – Apple Support (UK)
if needed, Set up watch for family member
Read the following link, which explains how to set up Apple Watch using Family Setup to your iPhone --> Set up Apple Watch for a family member - Apple Support