My definitions (I don't know what the proper terms are so I gave them my own names) -
Point - The end of the leather farthest away from you
Bottom - The end of the leather closest to you you
Bow - The opening made when you push two strips to the side
Practice on a strip about 2'-3' long. Longer than that and it gets really confusing as to what is what. Shorter and it's not worth the trouble.
A leather strip about 3/4" wide is perfect. Slit it into 1/4" strips being sure to leave 1/4" - 1/2" at the ends.
Work the leather bending it back and fourth until it's soft and flexible.
Step 1: Marking the leather
Step 2: Cutting the leather.
I found the best method for me was to push the point thru the leather into a piece of scrap wood then very slowly and carefully pull the leather thru the knife instead of moving the knife.