i never looked at those instructions. you're right. there's a LOT of information missing. :shock:
the size of the square tells you the width of the strip.
for example, if the squares should be 2-5/8", then you should start with strips that are 2-5/8" wide.
if you're only making one block, then you need:
two 2- 5/8 " squares from each fabric...
one 3-7/8" square from each fabric...
one 5-1/4" square from each fabric...
one 6-7/8" square from each fabric...
i'd heavily starch and lay down the two fabrics right sides together (so you're cutting both fabs at the same time to exactly the same size.)
cut a 6-7/8" strip.
cut the 6-7/8" square
next cut a 5-14" square from what's left of the strip.
then the 3-7/8" square
last, the 2-5/8" square
since i don't know how long your first strip will be (are you cutting full width of fabric? from a fat quarter"), i don't know whether you'll get all your squares from the first strip. the point is to cut the widest dimension needed first and get what you can from that strip before you cut another.