The nut that holds the spinnning water arm broke

You'll have to excuse me, but I'm a women and don't know the exact names for the parts.
Since my nut broke off in two parts, I had to remove the screws on top of the drain screen to get the other half. I just used a philips screwdriver and removed the 7 screws. Took out the broken part, and that was it. Put back the screws, put on the spinning water arm and put in my new part to keep it in place. Thank you. This saved alot of money for a repair person.