With pride! But seriously, Delta, by default is designed to be worn on the non-dominant hand. Wear the device one finger width above your wrist bone. The device should be snug, but comfortable.
Pssst: want a more accurate heart rate reading? Try wearing the Delta tighter/ higher on your wrist when exercising! It should not move while running or exercising.
The optical sensor is located on the back of the device.
Keep in mind: if you were to compare Delta tracking to the tracking of a third-party device, there may be a slight difference. General rule of thumb? A discrepancy of 5-10% can be considered acceptable.