Its probably best to fill it to about 2/3 of the tank to leave space for the pressurized air, although when first trying it it might be better to put less kerosene in.
It will be scary if it flames up, you will definitely need a frypan (or large saucepan) and/or a fire blanket out and ready to cover the flames just in case. If there are flammable things like curtains near the stove it is probably best to move them further away if feasible.
The procedure is to:
Pump up the air pressure in the tank a bit. I'm unsure, probably about 8 to 15 pumps, you should be able to feel some resistance to the pumping to indicate it has air pressure. If you are lucky that you have a pressure guage that still works, then I'm unsure what the pressure should be.
Ensure the kerosene is turned off at the burner.
If there is any kerosene visible at the burner or in the burner cup, first wipe it up with a rag.
Place some methylated spirits in the cup at the bottom of the burner. Light it with a match and let the methylated spirits burn for a while until it completely burns out.
It is very important, to avoid a flare up, that there is no kerosene in the burner cup when lighting the methylated spirits, and that the metho flame has completely burned out before turning on the kerosene flow to the burner.
Then turn on the burner and light it with a match or lighter or something. If it works, then the it will burn with a blue flame and hiss.
If it doesn't work, then yellow flames will flare up everywhere threatening the headliner, and anything else flammable near the burner, which you will need to turn of the burner and cover the flames with the frypan, saucepan or fire blanket that you have ready for this purpose. Then you would have to wait for the burner to cool down first before repeating the procedure, as HGO2 warns that it is dangerous to pour metho on a hot burner in this thread:
www.seabreeze.com.au/forums/Sailing/General/Boat-Heaters/Although they can be scary at first, I really like pressure kero stoves.
If you have never tried the burner before then there is a chance that it will be clogged up with carbon, so you may need to try another burner.
PS an alternative to using methylated spirits to pre-heat the burner is to preheat the burner with some type of gas torch, obviously that would require wiping up any kerosene on the burner or cup before trying that.