How can he light the gas in the fridge?

Turn gas control knob on panel to 'ON' and press it in and hold it there until the gas flows through to the nozzle and igniter.
This may take a few minutes if there is any air in the gas line following a cylinder change. You should hear a feint 'pop' when the gas burner lights-keep holding the gas knob in for a further 30 secs to allow the thermocouple to hold the gas valve open-then releasethe gas knob.

Geoff in Wales
July 2009