You cut the fabric at what measurements is given at first. The subcut is the measurements they tell you to cut from the first measurements of fabric. Like cut 2.5 inch by WOF. subcut that strip into 2.5 (which is already the width) by maybe it might be 6.5 inches. You cut as many as you can get out of that widith of fabric, of 6.5 long.
Clear as mud ah!!
If I have directions like that I have to go over the cuts, until I understand it. Just keep reading the direction until you understand them.
Keep it rocking,
Simple quilter