The picture may not be converged properly. Make sure the device is fitted properly to your head. The nose bridge should fit and secure on the top bridge of your nose and the lenses should be very close to your eye so that your eyelashes almost touch.
While on the test screem (default screen)
Position each eye such that the two images converge into one single, screen with square corners on the left and right sides.
Focus each respective eye by rotating the lens. It may help to close one eye and focus each lens respectively
Finally, closing one eye at a time turn the diopter focusing adjustments to see a sharp image.