Heart rate not recording and export data from iwatch


I am with my iwatch 3 and iphone 8. I selected the heart rate in the option but it did not have anything shown up on the app.I tested the heart rate with other app but it works fine.

When I select record with device( not on the phone). After finish recording, I could not find the previous record. How can I export those record back to my phone or laptop?

Many thanks.