[. . . ] Replace the black drum/toner unit, then push the lock lever toward the back of the printer as far as it will go. [. . . ] If TONER SENSOR ERROR appears when you turn on the printer, the lever for the toner cartridge color indicated is not pushed all the way back. Repeat these steps for the yellow (Y), magenta (M) and cyan (C) drums/toner units. Remove the fuser shipping restraint (A) and orange band (B) by pushing the restraint to the left, then lifting it out. Press + one or more times, until you see INFORMATION MENU on the first line of the display. Press - or + one or more times, until you see DEMO1 on the first line of the display. Install the Handy Reference Guide Remove the backing from the VELCRO® strip on the back of the Handy Reference Guide and mount it on the side of the printer. [. . . ] Install the Handy Reference Guide Remove the backing from the VELCRO® strip on the back of the Handy Reference Guide and mount it on the side of the printer. [. . . ]