Step 6: Sew in the ribbon with a lockstitch
First, center the ribbon within the fold. Visually estimate where the first hole in the fold touches the ribbon, and make a square knot using your needle and thread in the selvedge of the ribbon at that point. Cut the tail of the thread close to the knot. Draw the thread through the first piercing, moving from inside the fold to the outside.
Next, push the threaded needle through the second hole in the fold and up into the ribbon at the very selvedge edge.
Push the needle back out through the same hole through which you entered. Pull the thread taut, being careful to not tear through the plastic.
Move to the next hole and repeat the process. This is your lockstitch--it allows the ribbon to move freely to the right or left and out of the way of the text you are reading.
End by pushing the needle back into the ribbon at the point of the last piercing in the fold, knotting the thread around the selvedge there, and cutting the thread close to this last knot.