I did both my LR and BR toppers last year. Easy to do and the instructions above are good. If you want some more detailed instructions, go here: Slide Out Awning Replacement Installation Instructions
Just a couple of things I found when doing mine:
1. While it sure can be done with one person, 2 will make it easier and it's more enjoyable to share a beer or two instead of drinking one alone.
2. I used a strap wrench on the cap at the end of the roller to unroll the tube and hold it while I placed a large cotter key in the hole to keep it unrolled while I removed and replaced the fabric.
3. Be aware that the welt (I think that's what it is called) you insert into the grooves is a different size on each side of the fabric. I had my first one I reinstalled reversed and couldn't get one side to start in the groove. I looked at the other side and found it was so small it wouldn't stay in the groove...then a light bulb went off in my head and I was so glad I hadn't called the folks who made mine up to ask them about it.
4. I took my old toppers to a local awning manufacturer and they sewed up new ones for me made out of a much better and heavier vinyl than I could get pre-made...and for about half the money! Might want to at least check out some local place to see if they can do the same for you.
Good Luck with your project. Let us know how it turns out.