First up - the beauty of mitered corners... you have to do virtually nothing to the back of the quilt. Check out the first picture - how awesome is that?
The biggest thing to focus on when pinning the binding to the front is to cover up the stitch lines from attaching the bias tape to the back. Make sure to pull it over that and then pin. You can see those stitch lines in picture 2. :)
For the rest of the corners, simply fold up one side, then fold over the other. (As shown in photos 2-6)
Photo 7 shows how to reign in where the two ends of the bias tape meet - just keep messing with it until the edges meet up and it all looks nice, and then pin!