Help with pairing my Iwatch to my iPhone

The watch will need to be connected to the internet for this;

To unpair and erase watch and remove Activation Lock

From a web browser,sign in to iCloud.com with your Apple ID.

Go to Find iPhone.

Click All Devices at the top of the screen.

Click your Apple Watch.

Click Erase [device]. Select Next until the device is erased.

Click Remove from Account.

Did you unpair the watch from your old phone?,a watch can only be paired to one phone at a time.

If the watch is still paired to your old phone it won't pair with your new one.

Erasing the watch doesn't remove the activation lock;