Center Air Intake Grille, Removing And Installing, RS4 Basic/Lines From Product Improvement: Installing
WARNING: This page is about a different car, the 2021 Audi S4 and 2021 Audi A4 Quattro. However, it is still accessible from the selected car via links, so may be relevant.
Install in reverse order of removal and note the following:
-- Place the air intake grille on the bumper cover and push it on. While doing so, the catches must fully engage in the bumper cover.