Search for the ZY-8068 on sites like ManualsLib or ManualsOnline.
If the running belt shifts to one side, use the Allen wrench provided (or a standard 6mm) on the rear roller bolts. Turn the bolt on the side the belt has shifted toward clockwise by a quarter turn while the machine is running at a slow speed. Zy-8068 Manual Pdf
Most ZY-8068 units come with 12 pre-set interval programs. Press the "Program" button while the machine is stopped to cycle through these profiles. Search for the ZY-8068 on sites like ManualsLib