The following article will explain how to change the units of measurement on your device. You will need to do this separately for your dashboard stats and separately for your mobile stats.
1) From the home screen press the bottom left button to go to the settings section of the watch.
2) Press the bottom right button to scroll down the options until 'Units' sits in the middle of the screen. Press the top left button to access this section.
3) Press the bottom right button to scroll down to the 'Meters' option. Press the top left button to confirm your change.
This will now update your watch's units to meters.