How can pair a Apple Watch that has the activation lock from a previous owner

The Activation lock is an anti-theft measurement. The previous owner needs to unlock it.

This might be easy if you're friends with that person.

If you bought the watch from somebody that wasn't the owner, you need to get your money back.

Also, a Series 1 should just be recycled. If you do get the Activation Lock opened, there's a pretty good chance that you might not be able to get it to pair with your phone. Of course, this also depends on how old your phone is.

Here's is an article that is worth your time to read through:

https://discussions.apple.com/docs/DOC-250001038

The person that you bought/got this watch from needs to follow all the steps on this page;

Remove the Activation Lock so that the buyer can use it.

If they can't or won't then get your money back or recycle the watch and mark it down as a bad experience.

Neither the users on this forum or Apple can help you,only the original owner can help you.