How to connect my Apple Watch to my iPhone?

You can find the instructions on how to pair an Apple Watch to your iPhone here:

Set up and pair your Apple Watch with iPhone - Apple Support

If you’ve already tried this and are having problems, please read thru this article:

If you can't pair an Apple Watch with your iPhone - Apple Support

If you are still having problems after that, then please reply with as much detail as possible. We will need to know what iPhone you have and its iOS version. Which Apple Watch are you trying to pair? Exactly what is the problem? Is there an error message?

have you read

How to pair your Apple Watch with a new iPhone - Apple Support