Choose a backup to restore on used phone

[Elanine]

Hello - I just purchased a used Samsung Galaxy S8 (the old one is at the bottom of a river). When I am setting it up, it asks me to choose a backup to restore. I don't recognize these choices. Would these be from my old phone or from the previous owner? I already put my gmail account in.
Thanks!

 

[svim]

SM-T810 is Samsung's model I.D. for a Galaxy Tab A

SM-G950U is Samsung's model I.D. for a Galaxy S8 (note that it's dated early 2018)