The cover may be strapped down. Click the button on the end of the two straps to open it up.
Half a lid full of shock treatment should be added after each use in order to keep it clean.
If the hot tub isn't getting hot enough, check the mode - it should be set to Auto, not Economy. From the Settings Menu, tap up or down to highlight the "Heat & Filter" menu tab. Tap Heat & Filter to the enter the menu, then select Auto.
Operating instructions can be found
here.