The dust filter is installed behind the fan.
1. Remove the ventilation cover in the right footwell, first turning the mounting spring clip 1/4 turn.
2. Unscrew and remove back the protective cover under the glove box.
3. Press the spring latch and swing the cover back.
(Material taken from a web resource: MercedesMan.ru)
4. Pull the dust filter (1) downwards in the direction of the arrow.
5. Insert a new filter.
6. Insert the cover. To do this, move both retaining clips (3) in the direction of the arrow.
7. Install and screw the lower engine compartment cover.
8. Install the vent guard and rotate the retaining spring clip 90 degrees (1/4 turn).