Nostr is a place to start. Post it up on orange pill app, meetup.com, eventbright, etc. Also check out nostr equivalents. You can also post to reddit and message boards as well as flyers at your library and store. Those are all cheap/free options.

Hate to to say it but Twitter too.

I find word of mouth to be the most powerful for this sort of thing.

Also set up a telegram or some sort of official chat channel so you can organize and amass ppl together for updates and news

First few meetings might be small. Maybe it's just you for some of the meets. But be consistent. Choose a reasonable weeknight (many say Thurs night is best) and stick to the same time and location on a monthly basis.