Be sure that the surface is cleaned before applying graphics. A mildly soapy water solution may be used to clean the surface. For better results, rubbing alcohol (isopropyl/isopropanol) can be used additionally. Avoid using ammonia-based cleaners, as this can cause long term issues with the film and adhesive.
Fold half of marking back over hinge, peel liner off marking to tape hinge, cut liner along hinge and discard.