WARNING: This page is about a different car, the 2020 Audi A4, 2019 Audi A4, 2018 Audi A4, and 2017 Audi A4. However, it is still accessible from the selected car via links, so may be relevant.
Courtesy of VOLKSWAGEN GROUP OF AMERICA, INC.
-- Loosen the clamping sleeve -3-.
-- Remove the bolt -2- and push the clamping sleeve to the front and remove the muffler -1-.