I'm not sure where to get the manual but i can tell you a bit about the operation. I used mine in my home office for 8 years until it just died today.
The Power button switches between 2 modes on the heater, Auto or Manual. Press the power button once for Auto mode. Press it again for Manual. Press it a 3rd time to turn it off. The foot power button works the same way.
In Manual mode, the heater stays on until you turn it off. I'm not sure if there are any safety features in this mode. I never used it.
Auto mode allows you to set the temperature you want to keep the room. In Auto mode, press the +/- buttons to set the temperature. The Set light should be on. Once you choose the temperature then press the Power button again to set it. The Set light should go off. If you don't press the Power button again, the heater will reset to the previously chosen temperature.
The other function available in Auto mode is the timer. In Auto mode, press the Timer button. All 5 lights should be on. Use the +/- buttons to select the # of hours you want it to be on from 1-12. (This is the mode I always use.) Once it displays the time you want, you can press the Power button again to set it or wait 5 seconds and it will use that time. Once the time is set, there should be 4 lights on, all but the Set light.
Those are the basic functions of the heater. The heater will normally display the temperature in the room, not the temperature you set.
Let me know if there is any clarification I can provide.