I do mine the opposite way around from the instructions.
1. Centre then fit the lower part of the canvas with the fixing strips and screws, make sure you haven't got it inside out, fly net should be on outside.
2. Centre the rear (longer part) stretch and staple
3. Work your way left and right of centre a foot past the brace bars (leave enough room for you to undo the bolts on the bars)
4. Undo one bar and staple behind then do back up and repeat other side.
5. Continue stapling to the fornt just past corners.
6. Centre the front and work way back out to the sides.
7. You may need to pleat this end but it will be out of sight.
8. When you are happy this is tight enough double the fabric and go back over it.
9. Then use the original plastic strips and tap the staples back in.
10. I used additional screws every foot to make sure.
11. If you want you can trim any access off.#
I tried it both ways and found this the neatest, I have done 4 now and can do it in about 2 hours.
Here are 2 that I diod this way:
Just let me know if you want me to explain further.