Coleman 7900 series gas furnaces do not require owners to light the pilot light with a flame. There is not a lot of other work that you should need to do with the furnace aside from changing the filter from time to time. However, if there is a problem, you can reset the furnace to decrease the likelihood that a temporary setback becomes a permanent problem.
Set the thermostat to the "Off" position.
Open the breaker box and flip the switch that controls the furnace to "Off."
Lift up on the upper door panel to remove it.
Slide the gas valve control switch to the "Off" position.
Wait five minutes for gas to clear out of the system. Smell to make sure there is no gas present before moving on to the next step.
Slide the gas control switch to the "On" position.
Place the upper door back into place.
Slide the switch in the breaker box back to the "On" position.
Set the thermostat to the appropriate setting.