try this
https://www.samsung.com/us/support/answer/ANS10002867/?msockid=2ca2735441aa6b800e0d661e40296aa0
- From the watch's Home screen, press the Power key.
- Navigate to and tap Alti-Barometer.
- Review and allow the required app permissions.
- Tap Go to calibrate the altitude sensor for the first time.
- You can recalibrate the altitude sensor at any time by tapping the Refresh icon at the bottom of the screen.
- Swipe left or right to toggle between Altimeter, Barometer, and Settings. To adjust the app's settings, tap CHANGE.
The following settings are available:
- Auto refresh: Turn on or off the auto refresh setting.
- Manual calibration: Manually set the altitude and sea level pressure.
- Pressure alerts: Turn on or off the pressure alerts setting.
- Altitude unit: Choose if altitude should be measured in feet or meters.
- Pressure unit: Choose if pressure should be measured by hPa, in Hg, or mm Hg.
- Help: Explanation of altimeter, barometer, and pressure alerts.