One of the best ways to apply our static grass is to use a thick white (PVA) glue and then sprinkle the grass on it until covered. The glue dries, typically, to a satin clear finish but is usually not visible.
You are certainly not limited to using just PVA glue however. There are many types of adhesives that will "work" for basing. We are only suggesting the "best" medium for the use with our products.
What's it for?

Typically, static grass, is used to cover areas of a base, vignette or diorama in cases where an unkept type of grass would normally grow. The taller strands stand out much more visusally than flock would. Flock is used for a different look.
Inspiration?

Of course there are many different ways to use static grass... I've seen people add it to a miniature's face for a beard effect. I wouldn't recommend doing this, but please don't let my doubts stray you from being creative. However, adding it to a miniature's boots, I think it makes the effect more realistic.
Alternative uses?

Adding static grass to buildings creates a very unique and very cool looking effect. It appears as overgrowth has taken over parts of the structure. Much better looking than flocking that same area. Also, adding only patches of static grass to certain areas can look way more realistic than covering the area completely with the grass.