WARNING
For safety reasons, switch off the windshield wipers and remove the key from the ignition lock before changing the wiper blades (vehicles with KEYLESS-GO: make sure that the on-board electronics are in state 0).
Otherwise, the wiper motor could be switched on suddenly and cause injury.

To avoid damaging the wiper blades, make sure that you touch only the wiper arm of the wiper.

Never open the hood if a windshield wiper arm has been folded away from the windshield.
Never fold a windshield wiper arm without a wiper blade back onto the windshield.
Hold the windshield wiper arm firmly when you change the wiper blade. If you release the windshield wiper arm without a wiper blade and it falls onto the windshield, the windshield may be damaged by the force of the impact.
Mercedes-Benz recommends that you have the wiper blades replaced by a qualified specialist workshop, e.g. at an authorized Mercedes-Benz Center.