Here's how you can install the BetterMe app on your Apple Watch:
- Open the Apple Watch app on your iPhone.
- Tap My Watch → General → then turn off Automatic App Install.
- Tap My Watch → scroll down to Available Apps.
- Hit Install next to the BetterMe app.
BetterMe app offers Step Tracker and Water Tracker features and Walking and Running workouts on Apple Watch.
You may find the following article helpful: How to track steps with Apple Watch.