This is what I do to make it super easy to install:
1) trim a piece to size (a little larger than needed).
2) remove extra clear film off the back/smooth side of the window film. If the window film has a pattern, the bumpy side is the front & the smooth side is the back.
*See my video on removing the extra film backing off the main decorative film.
3) use soapy water vs just plain water - this seems to work better, but plain water will work as well, it seems.
4) spray the smooth back side of the window film with a light mist of soapy water.
5) spray the cleaned window surface with a light mist of soapy water.
6) position the window film onto the window. You're basically putting the wet surfaces together. This will give you enough slip to slide the film around to achieve the correct position.
7) squeegee the water & bubbles out from the center to the edges. Using a towel to wipe in a squeegee-ing manner helps, too.
8) trim excess as necessary. Squeegee & wipe a bit more as needed and that's it!
It's easy to remove completely and reposition as well. There's no residue left behind.
The 78 inch roll is a great value and I was able to install a privacy strip on a bathroom window (not the full window so light can come in for the plants, but enough to block other 2nd floor neighbors from seeing in), a narrow window by the front door, & still have a little excess.
Privacy, beautiful rainbow reflections (if in the right level & angle of sunlight), looks stunning, sturdy film, and easy to install! Highly recommend.