When you go to bed press the side button to open the control center.
Press the crescent shaped icon and then sleep.
When you wake up press and hold the crown wheel until the watch “wakes up” and then the side button. Then press on the crescent to turn off sleep mode.
You will then get the results sent to the phone’s health app.
Hope this helps you.
Have you tried to set it as though it is on the right wrist?
This way the movement would be the same as if the watch is on the right.
Just a thought