The best thing about using the school glue is, once you iron it on, the binding can be pulled back up and re-adjusted if necessary. It only takes a small thin line of glue. As long as your seam is sewn straight, put the glue on that seam, then press the binding down and iron. Use a dry iron, no steam. Place pins in the binding or use the binding clips.
I find that when mitering the borders, the side I am gluing, is the side I glue down all the way to the edge of the corner. Then I start a few inches away from the corner on the adjacent side and glue down the binding going toward that corner. The miter appears in the corner because you have already created the 45 degree angle from the other side that went to the very edge.
I use the bottle tops for the empty coloring bottles sold at beauty supply stores. About $2. (Clear bottles with black tops are at our local store.) They fit perfectly on the school glue bottles. The tip is elongated and makes a perfect thin line of glue.