First I take one of the shoe strings and place it in the grasp of my little arm.
Using the arm with the hand, I tie a knot and pull on both strings.
I make a loop still grasping the string with my little arm.
Next I move the loop behind the grasped shoe string.
Then I pull the grasped string straight towards me and over the loop. With my little arm I grab the loop and take the loose string through the hole, making a bow.