How do I check steering fluid on 98 C230
 

My manual does not say anything regarding this. i just bought the car 3 months ago. Do I check it hot or cold? Also when I unscrew the cover there is a dipstick built into the cover. At the bottom it has a min hash mark with 20'c next to it. There is also more hash marks above this one and one of them also says minimum. The top hash mark says max and it has 80'c next to it.

Should I only use MB fluid as the fluid chart indicates?

You can check it either hot or cold. The lines that correspond to 20C mean 20 degrees centigrade. The level should be there when cold. When it gets really hot after driving for a while, the 80C line should be used for the reading.