How do I replace the lightbulb inside my Advantium 120 oven?

I've found the answer (sort of) by searching online, but the pictures are so small it's hard to see. The oven cooks OK, but we need to get in the top, I think, just to replace the light bulb.
This is an Advantium 120 oven/microwave combination inside our RV. There was a flash and the light went out. Obviously they want as much money as possible now the warranty has expired. There is no info any where in the book about this problem, and it should be a simple fix. Any help will be very much appreciated.
Thank you, Annie Perkins