I expected at least two guards! We have one and still have to understand how to put it on the screen ... For my part I reversed the screen next to the one that sticks. Must say that the explanations are in English and not English easier!
In short, I managed to put it without too much damage. after rubbing the screen for 5 minutes with the cloth I still have to finish two bubbles in the middle of the screen ... but that's for all the protections ...