The first thing you want to do is drain the coolant. You might as well drain all of it and replace with MB 50/50 mix.
To drain radiator there is a red screw behind the driver's side tow hook cover. To drain the engine get under the car (remove small cover 8mm), look at the block straight up. You'll see two nipples on both sides right in front of the engine mounts. I believe it's a 5mm allen, a socket type will make the job a snap.
Once you drain all of the coolant you can remove the fan shroud. Pretty easy, it's a two piece system. Then you take the bracket off from the top of the car remove all hoses and transmission fittings and you can pull it out (top). Reverse installation just be careful with the transmission fittings, don't move them around too much and watch out when reattaching.
Coolant just pours in. Put in until you reach the top, turn on engine and keep pouring until it's full (slightly more than 2 gal). Check for leaks both tranny and coolant.