I use the 3M as well (15") as mandated by our security team. They work too well...when I'm sitting next to a coworker on a flight, we have to remove the screens so we can see.

There are 6 tabs about 1/2" long that stick to the outer bezel of the laptop. That leaves about 1/4" of the tab that sticks out into the screen area (the tabs are clear). Two tabs go on the left, right and bottom of the bezel and they form a "pocket" that holds the filter in place. It's nice because I can leave the filter in place even with the laptop closed.