Can't find data to transfer from iPad to refurbished iPhone

back up the iPad to iCloud.

Make sure that you erase this new phone back to factory settings.

Then set up the phone using the backup from earlier.

You must use the same Apple account as on the iPad and when you finish setting up the phone, you need to rename it in settings General about, because it will have picked up the name of the iPad.

How to back up your iPhone or iPad with iCloud – Apple Support (UK)

Erase iPhone – Apple Support (UK)

Set up your iPhone or iPad – Apple Support (UK)

Are you logged in with the same apple account that you want to set up your iPhone with? Is the iPad running a software version that supports quick start?