Yes, you're in. I use Flotilla on mobile where you click the three dots at the top and the Groups screen slides out. That's where you click the create room option, give it a name, set the permissions of who can see/read/write to the group. You then send out 4 invites. Each invite you send out can then also invite 4 more people. Each of them, another 4 etc. Or, if you just set the room permission to public, then anyone can join. Or, you set set permission so public can read it, but only members can post.