Hi Tbower,
Are you talking about the knob on the far right that generates a spark to light the rangetop burners? I've never found it to be very good. Ours generates a spark, but it's so small that for it to work the gas has to be on too long in my opinion. There's always a large flareup when it finally ignites. I have a couple of fireplace butane lighters and a handheld spark striker that work much better.
The ovens are lit manually by pressing in on the knob while applying flame to the pilot light assembly. If you leave the knob in the pilot position, the pilot light should stay on as long as there's no interruption in propane supply.