i need help to connect my watch to my phone

See these two support articles:

If your Apple Watch isn't connected or paired with your iPhone - Apple Support

If you recently got a new iPhone and you failed to remove the watch from your previous iPhone, see the following link:

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

See the section on If you didn't unpair your watch from your old iPhone.

See also the following Apple articles:

Set up your Apple Watch -> Set up your Apple Watch – Apple Support (UK)

The Apple Watch app -> The Apple Watch app – Apple Support (UK)

Apple Watch user guide -> https://books.apple.com/book/id6442854652

Apple Watch Support -> Apple Watch - Official Apple Support