If I had to guess I would say that you cut 8 1/2 X WOF (width of fabric) and then you will subcut.
I just looked up the pattern.
Are the big blocks 8 1/2 X 8 1/2? Then you would also be using strips ?(width, maybe 2") X 8 1/2.
I can't find a link to the pattern and I am only looking at a picture so I am really just guessing.
Hopefully someone has actually made the pattern and can be of more help.
Good luck,