Find a place, announce far and wide and they will come.
Initially just introduce around and ask eash to tell their experience with quiting. You might have a short demo of some kind, or pass out a paper giving hints about quilting.
Ask for show and tell. After a meeting or two in which you do all the ploanning, then ask if someone will do a demo at the next meeting. Ask if anyone wants to meet regularily for a "sew in bee" Eventually you might find the group will need a bit more structure to keep the interest going and the group alive. If the meeting place is free - so much the better but even churches and other pubic places have to pay the heat and lights so you might take up a donation for that or set a certain amount but low.
Ask to bring excess suppies for trade or to give away. And you are on your way.