I ordered a sample of this and there is no adhesive to the film. Is it available with an adhesive back, is it static cling, or do I spray an adhesive onto the window? Does static cling work when over

The SXP series of film is an adhesive product, not static cling. The samples are cut from actual rolls of film. There is a clear liner on the back, although sometimes it can be tricky to get started. See the instructions here: https://www.decorativefilm.com/installation-instructions. These films will overlap and stick to each other just fine. Try using 2 small pieces of tape on each side of the film and then pull them apart.