The Basic social unit would probably be the commune or council which would federate to a wider body, say the region or province. Delegates from the councils would form bodies that would concern themselves with issues of relevance to their mandate. However, federalism alone cannot create or preserve a free society. It must be combined with the elimination of centralised power, hierarchy, authority and inequality. Where these are preserved federalism becomes a sham.
Free federation is possible.
It is the task of revolutionaries to create it.