Unplug the oven's power cord from the electrical outlet or turn off the breaker switch that controls the kitchen. Shut off the stove's gas supply valve.
Remove any racks or pans that may be inside the oven. Unscrew the retention screws at the rear of the oven that hold the bottom pan onto the rest of the unit.
Remove the wing nut that holds the flame spreader in the center of the oven floor in place and gently lift the flame spreader up to expose the igniter.
Remove the mounting screws that connect the igniter to the oven floor. Find the plug-shaped quick disconnect at the bottom of the igniter. This connects the oven's electrical wires to the igniter. Pull the quick disconnect plug away from the oven and remove the igniter.
Insert the replacement igniter into the spot where the old igniter had been. Insert the quick disconnect plug into the new igniter. Tighten the mounting screws to secure the igniter in place.
Replace the flame spreader and oven floor by reversing steps 2 and 3. Plug the power cord back into the electrical outlet or turn the breaker switch back on to restore power to the oven.