Trick or Treat in the City

Hello Fellow Ft Greene/C.Hill ers. I'm fairly new to the neighborhood and New York in general, and I wanted to know how the whole trick or treating thing works here. Do children trick or treat in the traditional sense? Will they ring my buzzer in my building since I live in a smaller Brownstone Apt? Should I have candy ready? Do I put up a sign inviting trick or treaters to buzz? This may sound like a ridiculous question, but I just wanted to get a feel for how it works in the neighborhood. I also realize that it may vary from building to building and block to block.

Thanks!