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

Tailgate Clear Protection Film (PPF) for Rivian R1T Tailgate Clear Protection Film (PPF) for Rivian R1T