Original Apache heater controls are between the pilot seats. There is a fuel shut off (reostat type clockwise to close, couter clockwise to open) that must be opened before operating heater. Otherwise when you turn it on all you are doing is blowing more cold air in on you! Other than that it works just like most others, Hi, Low, and a vent mix control push pull knob. It works well but takes time to heat up, and if you do not have the mix air right you over heat the heater and pop the breaker, OR you pump too outside air into the mix and never get it warm.
Takes a bit but you will figure it out. Just remember to check for leaks on that fuel shutoff knob, and to shut it off after use. (I think the book calls for shutting off the fuel and burning the heater till it goes cold to not leave fuel in it.
Many Apaches have been modified to a newer style system, but your question seems to imply that you have the original screwy one.
Hope this helps.
P.S. Did I say check for leaks?? I did. Oh yeah, just remembered...check for leaks....!! Make sure you go full on or off on the fuel control knob, meaning to the stops, anywhere in between and it dribbles fuel into the belly and floor, could be bad for obvious reasons!!