Bottom Panel of over rusted out.

Unplug the stove from the wall socket. Remove the oven door as shown in the instructions for replacing the door. This makes the job a lot easier. At the rear of the bottom panel there is a screw at each corner. Remove these screws, a screwdriver will loosen them, then remove by hand. If you have a convection oven remove the fan cover as this prevents the bottom panel from coming out. There is a screw at the top and the bottom of the cover. You can then gently lift the bottom panel at the rear and work it out of the front lip. Install the new bottom panel in reverse order.