Judy
As jstich said the triangles are supposed to be bigger than the squares just fold the triangles in half & the squares too. Then match the creaseline of the triangle to the creaseline of the square & sew away. You will have an overlap at the end but your be fine :D
Practice it on some other spare fabric you have to see the result if your abit confused. That's what I always do is practice blocks with spare fabric. Hope this helps. :wink:
Tisha