You will want to do this in 70-80 degree weather ideally.  Stay in the shade. 

Apply application fluid to the target install and nearby surrounding area.  Also apply it to the back of the PPF as it is removed from the backing paper.  Apply it to your fingers for bonus points.

With a liberal amount of application fluid on the target area and PPF, you can change the alignment of the PPF by gently pulling up on portions and setting it back down.

Once you alignment is ideal, you can start to squeegee out the liquid with your hands and / or a small squegee.