Hi
If you cannot progress beyond the software version checking stage for your Apple Watch (even though it states that your watch is up to date), then your iPhone may not be running the latest version of iOS (and nor may your Apple Watch be running the latest version of watchOS, despite the message):
First update your iPhone to the latest version of iOS (start by making a backup):
Update the iOS software on your iPhone, iPad, or iPod touch - Apple Support
Then pair your Apple Watch by following the remaining steps here, if necessary including contacting Apple Support via the link in the support article: