Rie of CraftyRie asked "How do you use it". In the photo below you see it as a guide for the sewing machine (purple thing). It is peel and stick, so you can move it around to make any sewing edge you need. Such as in sewing garments most of your seams are 1/2" but in quilting it is 1/4". If you have trouble sewing a straight line or don't want to purchase multiple feet.
When I am piecing at times it is easier to put the seam edge to the left to get that perfect fit. This works well when you are piecing sections of a quilt together and you want the seams to line up.
I hope this clears up the confusion on how to use the Qtool Sewing Edge. For piecing quilts or sewing garments I find this tool vital for straight seams!
Thank you for reading today! Lisa