Ok, then you should have gotten from the video to look for a message that would state that "This item has been lost." That would indicate that the owner, placed it in Lost Mode. This is where they would have the opportunity to supply additional contact information, like their email address or full phone number.
It appears, from what you posted, that they did not do so, or did not want to use Lost Mode. As such, there is little you can do to find out how to contact them. Apple will not get involved either.
... so, you have a few choices:
- Wait a bit longer to see if the owner enables Lost Mode and provides their contact information, or
- Take it back to where you found it and leave it there. If this location has a "Lost & Found," take it there.
Should neither of these choices work for you, just be aware that this AirTag will be useless to you. Even if you reset it, it will still be associated to the owner's Apple ID ... and only they could remove it so it can be used by someone else.