Ditto Scott and Tom...in your newer model you simply set the thermostat to heat (furnace), set the temp so that it is higher than the current interior temperature and the furnace should come on in a bit... The blower will come on first, then you will hear the electric ignition click to fire the heater up.
It was unclear to me if it's not lighting or if you just don't know how it's supposed to be turned on. If, after trying the above process, if it tries to fire up three times in succession and fails, then the furnace will shut itself down. Turn it off at the thermostat and let it sit a few minutes so that it resets itself...then turn the furnace back on at the thermostat and try again. If the blower goes on but the ignition is unable to light the heater, there may be one of several things going on: (a) the ignition is not getting enough power to successfully light the heater; (b) the sail switch is stuck; (c) there's a problem with the furnace board; (d) there is a problem with the gas regulator and it is not getting enough gas. The later happened to ours, discovered only when we were in colder temps...we had to have the regulator replaced (under warranty). Check out this sub forum for more information on furnaces: http://www.airforums.com/forums/f427/
Since your unit is so new, I'd suspect the regulator or lack of proper power first (but I'm no expert and it doesn't mean it couldn't be other issues). If it continues to give you trouble, it ought to still be under warranty, so yoiu can get it fixed, whatever the problem is. Hope this helps!