I can only speak frlm my experience. I have built multiple communities and they all started the same. They all went something like this: 1) Somehow I met someo

I can only speak frlm my experience. I have built multiple communities and they all started the same. They all went something like this: 1) Somehow I met someone who is also passionate about the domain (online, friend recommendation kr meetup) 2) Create a meetup for the subject and have me and the other the speakers while finding a sponsor or two (not as hard as you think) 3) The meetup grows to a monthly meetup and a social media group gets created. 4) Sometimes a website is needed for mailing lists, blog posts and announcments. Some don't last very long as they are based off a trend (Blockchain for example) and some have survived until today. Good luck!