Hi, I don't have a 560 SL.
But I will try to help you.
Your car has multiple belts 5/6
You start with one closer to you when you are in front of the car.
You need a set of sockets and ratchet, combination open / box wrenches and in your case I think a socket with a
5mm Allen to louse the power steering pump adjusting screw.
If I am correct the first belt is for the air pump.
Next two belts for the alternator.
Then the air cont. compressor.
And last the power steering, water pump.
You have to louse a lots a bolts fore each system, and they also have tension screws.
I would suggest to get a manual to help you.
Changing belts is one of the easiest jobs doing on the car.
I have replaced hundreds of them so it is easy for me.
But I don;t know how able you are.
Hope this helps you a little.
Regards,
aam.