I'm far from an expert on this type of scope, however, I do know a couple of things, and have some more suggestions, now I can see pics.
The red knobs should be set to the "Calibrated" position, where applicable. For the "Stability", turn it to "Preset". For the "Triggering Mode", set it to either DC or Auto.
The "Trigger Slope" I would set to "Line" either + or -, which should trigger off the mains waveform the scope sees on its own psu, so should trigger even if the other trigger levels aren't set correctly. The "Time/CM" should be set to 5 or 10 milli sec, the "Horizontal Display" I would set to "Time Base".
Have you any leads or probes? With the input ungrounded, with a lead or probe connected, you should see some 50Hz noise, with any luck.
EDIT: I have paged Papa Smurf...