Okay how do I trinkets or whatever this is my first year and I haven't been on a lot lately so...? yeah o-o

You dance with other people for the trinkets (with a mask on) and turn them in the Steamworks Menagerie or Libertine Lounge and buy stuff C:

And how do I go about dancing with someone?

You can go to the Atebus Revolution Masquerade forum and there's an option to dance with people in the posts

You can only dance with people in the dancing forum, called Atebus Revolution Masquerade. :) Under where it says 'xx Posts, xx achievements' for someone, it will say 'Dance with xx'.