Publicity Coordinator should take care of advertising this, but you might need to email tech-squares-interest about intro night anyway.
You should try to be set up outside the club room by 7:30 (assuming club starts dancing at 8:00, and class at 8:15). You'll need the following:
When people have checked in, encourage them to watch the club dance. If you're in Lobdell, the balcony is ideal. Have some club person to chat with them while they watch.
As Intro Night if often held as an IAP event, MIT wants some data on attendees so you'll want to try to collect this. If needed, you can use email addresses to search for what year MIT students are.
I don't think we've done this recently, but consider asking the cuer if he wants to teach/cue an easy round that would be accessible to new people.