I found this method for affixing the magniloupe to my reading glasses very helpful.
FYI, in case you don't have a magniloupe, you can get one at an electronic store. Thats where I got mine.
Step 1: Parts Required
2. Magni Loupe
3. Rubber band
Step 2: Place Magni Loupe in position
Step 3: Place rubber band in position
Step 4: Twist and slip
Holding the loupe and glasses together, bring the rubber band around the loupe as seen in the picture. Sorry if it's not too clear. Each side of the band slips over and to the opposite side of the loupe, thereby holding the loupe in place.