To attach two hints:
1. It is best when attaching a second person to ask for help (someone who has a bit of tact)
2. Because the display is quite long, it is advisable in my opinion NOT for the film to attach from the top down, but from the side (ie from right to left). This allows you to emphasize the bubbles out well with the broad side of a credit card.
All in all I find the product for that price recommended. I subtract a star because the stylus after a while leaves a few traces on the rather soft film. If that bothers you, the film can change either every two months or have to just buy another. I do not mind and the film remains on it until it detaches itself!