The nice thing is, the instructions are in English.
I went with some feint of heart travelers that were barely able to trust we wouldn't get lost. I found the ticket vending machines to be very self explanatory and the maps of the system easy to read and follow.
On one ride a car had about a half-dozen people in Chelsea (football) colors. A bobby stood in front of the car door and suggested riding in a different car. I noticed there was a bobby at each station keeping an eye on the potential hooligans.
Mind the gap.