The film itself may be coated with a layer of glue. Thus it's no need to use other adhesive tapes. If you use double-sided adhesive tape, I recommmend this kind. This kind of tape won't fall off even if it ages owing to damp and high temperature. If the film feels not adhesive, it doesn't mean it's not coated with glue because generally, the adhesion of protective film is very low that you can hardly feel it.
