I feel like I'm only getting one side of this here-
Did they explain how things were supposed to be done and you didn't listen? Did they explain things and not do a good job at communicating? You are only telling your side of things, it's very hard to guage the situation without having any concrete facts here.
I work in a resturant and I can tell you its easy to mop floors however, it's a 3 step process of 1) Sweep the floors 2) Mop them with cleaning fluids and 3) Put a wet sign up, so nobody slips on the floor. I don't know how you were taught, but its basic, and I'm not sure how you are messing that up to be honest!
You should discuss this with your manager, ask him what he thinks you are doing wrong and ask him how he things it should be done the right way.