My advise would be to let your phone cool down for a moment. Just take off the battery, and just let your phone be(yea I know it's hard for most of us!). After ten minutes, start applying the protector.
When cool(protector) and hot material(screen) are mixed, it causes air bubbles
And thanks for the tutorial. I tried to apply a protector for my phone yesterday, but I failed, and lost two protectors. The other one's on my screen, and it has at least six large air bubbles at the bottom of the screen :cheers:
Fortunately they are those 5 pieces per pound(@Ebay) screenies!