They're not all going to be the same. You should consult your owner's manual. If you don't have one, find the make and model number of your heater. Then use the Internet to look it up.
If you still have the owners manual read the instructions. If not be sure the gas feed is turned OFF and the room is aired out (in case there's been a gas leak). Now you can turn on the gas, listen for the hiss and light it.
Most gas heaters come with a push button in order to start the pilot. You need to push down the button until the flame appears and the pilot continues. There is usually a knob that should be set to pilot to keep the light on once you have gotten it lit.
The best way to light it is to get a long handled grill light, remove the cover to the heater, light the lighter and place the tip under the pilot light.
You need to make sure the gas is turned on and locate the dial for the gas on the heater. Most you have to turn and push in and then you light it, hold it in for about 30 sec, the turn it to on. be very careful!
If its a manual type, turn knob to pilot. press knob in & light pilot & keep holding knob for about 30 seconds after it's lit, then release knob. if pilot is still lit, turn knob to " ON ".
