https://actionlab.strongtowns.org/hc/en-us/categories/360004233911-Local-Conversations

You are not required to be a member to start a chapter, and from all that I’ve seen, they’re very supportive of you send an email asking for guidance. I would start by going to local city councils or board of supervisor meetings, put flyers up at the library and small coffee shops or anywhere else you can put up flyers, and start holding regular meetings at least once a month