If you purchased just the top section, allow 20 minutes for the installation, for both sections, it'll be nearer an hour. Please watch the video below for a quick guide. Try to install when the temperature is between 60-80f (15-27c), so that the PPF is easy to work with.

The part in this guide

Película protectora transparente para portón trasero (PPF) para Rivian R1T Película protectora transparente para portón trasero (PPF) para Rivian R1T