I did both my slide out toppers and it was simple. The secret was the RVGEEKS YouTube videos. I watched them about 2 or 3 times just to make sure I caught every detail and it was amazingly easy.
They recommend Tough Top Awnings and that is where I got my new material from. It's top notch and they were very professional when dealing with them. I think they still have a discount code for the RVGEEK viewers.
RVGEEK website http://thervgeeks.com/awnings-and-slide-toppers/
Tough Tops website http://www.toughtopawnings.com/index.html