“And Moses did as the Lord had commanded him, and the congregation were assembled…” (Lev. 8:4). When leader and people do as God commands, a community forms by itself.
As an author of synagogue histories I have found this time and again. There was often no need for an official meeting with minutes and resolutions to create a community; the community formed by osmosis once a number of individuals found themselves praying and listening to the Divine Word.