Automatic automatic transmission problems

Good afternoon everyone.

I have a Mercedes A-Class automatic, and I'm having transmission problems. It seems to be leaking fluid from underneath, and none of the gear selector positions work.

I'd like to know how to top up the transmission fluid, but it doesn't seem possible, as the manual says only an official Mercedes service center can do it. Is there any way I can do it myself?

And if anyone has the workshop manual for this car, I'd really appreciate it.

Thank you very much.