To light a burner with underknob ignition, push in and turn the associated control knob to the high position as indicated by the large flame symbol. The igniter should spark and light the gas. Continue to press in the knob to let the gas through to the burner for about ten seconds. If and when you let go of the control knob or the burner goes out, then the FSD (flame failure safety device) has not been bypassed. Turn the control knob to the OFF position and wait for one minute before you try again, this time making sure to hold in the control knob for slightly longer.