The first rule of brake work is to remove the cap from the brake fluid resevour and cover the opening with a clean rag. This will prevent brake fluid from overflowing into the engine compartment.
Whether or not it is likely to overflow when you spread the calipers depends on how full the resevour is but it's always a good idea to cover it.
To remove the rotors, remove one of the bolts from the caliper and swing it up. Then I believe there is a 5mm hex bolt holding the caliper on. Take that out and tap on the rotor to free it.
The new rotors have an anti-rust covering that no longer needs to be removed. The old ones had a blue covering that always took me longer to remove than it did to change the rotors.
Don't forget to put MB anti-squeal paste on the back of the pads. Use Dot 4 or Dot 4+ fluid.