How can I change Screen Time settings on my Apple Watch Series 2?

After a certain time, most apps on my Apple Watch (series 2) are limited due to Screentime settings. I never set them. But when I go to the Apple Watch app on my phone to view/change the settings, Screentime does not appear as an option anywhere. How can I view/change the settings?

[Re-Titled by Moderator]

Original Title: Screentime on Apple Watch