To machine the binding on all the way I cut 2.5" for quilts but 2-21/4 for smaller projects, I sew it to the back and fold it to the front fold it over and sew it down, If you snug it in it will fold over more, idealy it will be the same on the front to the back, you may have to play with the width a little to suit how you put it on.
When you sew to the back there is the seam to follow in the front, following the line you can fold the binding just past it to make sure it is covered.
To help with the mitered corners when you come to the corner, tuck the side you are sewing in flat and have the corner out, use a small stick if you are to close and can't get your finger in there. it takes a bit of practice.