First off, with all types of cleaners, make sure to test a small inconspicuous area before proceeding to do the whole thing. This will save you a huge headache down the road if the product has a weird reaction to the material that is being cleaned.
But this product is super easy to use. The method for the product you currently have is to:
1) Spray directly onto stain
2) Agitate with a brush or cloth
3) Wipe off and dab surface to dry