Hi,
What you can do is open Network Watcher in the Azure portal using link below:
https://portal.azure.com/#view/Microsoft_Azure_Network/NetworkWatcherMenuBlade/~/overview
Click the Add button, select Region(s), then click Add button to deploy. If NetworkWatcherRG resource group doesn't exist it will automatically be created and the new network watcher will be deployed into the group.
If the above was helpful please click Accept Answer.
Thanks.
-TP