1. Turn on gas at the gas bottles (open the valve VERY slowly).
2. Light one of the burners on your stove and turn it off. This may take a minute or so. This is to help purge any air out of the gas line.
3. Set your thermostat to "heat" and set it to something above what you're at now. Say 70 degrees.
4. The fan should start, then it will try to light 3 times. If it fails, you have to turn everything off to reset, then try it all again.
If it's a Suburban furnace, I've attached an owners manual. If you still have trouble, this link may help you: http://www.beamalarm.com/Documents/t..._problems.html
Some other comments:
a. If you have an analog thermostat, don't expect it to hold a certain temperature very well. Most of us replace the analog with a digital.
b. You don't say what you're running with respect to electric. The standard 1500 watt electric space heater will pull about 12-13 amps. That doesn't leave much margin on a 15-20 amp circuit. Definitely won't run 2 of them.