How to operate gas starter fireplace?
First, the valve on every one of these I've seen is outside of the firebox. Any pipe beyond the valve is going to be empty of flammable gas in a short time.

The idea behind these devices is that they replace newspaper and kindling (or however you start your wood fire) with a small gas flame. You turn it on until the fire is going  then turn it off. 

You don't have to use this, you can start your fires the more traditional way and ignore this device.

If you are going to use the gas starter, you'll need to keep the firebox fairly neat and tidy to avoid burying the starter burner.