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.
-- Slide the antenna wire -2- into the cutting device -1-.
Fig 1: Pushing Antenna Wire Into Cutting Device
Courtesy of AUDI OF AMERICA, LLC
-- Close the tool then open it again.
-- Pull the antenna wire out of the cutting device.