The stratas are made from fabric that is cut in half, so each strata's width is approx 20 - 22".
I think what makes cutting the wedges so confusing is the ruler at the shortest end doesn't start at zero & it tells you to cut wedges so many inches long.
Sooooo, I put the wedge ruler's smallest end at one end of the strata. I cut the longest wedge. Make sure the horizontal marks on the ruler are lining up with the horizontal seam lines on the fabric. You're NOT cutting wedges on a diagonal. You cut every wedge after that 3/4" shorter. I used a small square ruler (it could be any size) that I put a piece of glow line tape at the 3/4" mark. After I cut the first wedge, I moved that ruler over where I would be cutting the next wedge & aligned the glow line tape 3/4" up from the first cut. I butt the end of the ruler against this little ruler. Keep doing this until all your wedges are cut. The last wedge you cut will be 3/4".
Another confusing area is how to cut from your stratas. Cut all the wedges (in one direction) that you can from 1 strata. Set it aside. Start cutting on the next strata with the size you need. This is where you will have to measure the last wedge cut & cut the first wedge 3/4" shorter. Keep cutting until you can't cut anymore. b
Next you will cut the remaining wedges from the opposite end. Cut from the wedge shapes of fabric left, until you cut your last one which is 3/4".
It's easy after that. Sewing the wedges together goes very fast. I think it helps to lay out a few of the wedges making sure you sew them tog. in the right order.