Glory to Jesus Christ!
Hello Holden,
I see you have already received an answer to this from Joseph, but I typed it so I guess I’ll post anyway.

Autonomy means that something has it’s own name, your Eastern catholic churches are like that. Mission countries will generally require guidance and support from outside, thus they might be known by a name like “Orthodox church of Patagonia” or something like that but ultimately are guided and financially aided by a mother church. The goal is to build up the church until it can support itself and launch missions itself, opportunity permitting.
Autocephalous means something is self headed, in other words self governing. Your Papacy is autocephalous.
It may escape a lot of people, but the early church was simply a collection of autocephalous churches. The cohesion came from mutual recognition. Synods and councils (generally local) received their practical authority from the bishops who participated in them. The bishops themselves are developed through the local synod and consecrated by the local synod.
Councils were a regular occurrence at the local level, and still are. In between these, the business of running a diocese (or synod of dioceses) was in the hands of the particular bishops. There is no magic to it, bishops often wrote each other letters for advice and continuity of policies. Today they can (and do) pick up the phone.
If you are wondering how the whole thing continues to hang together, it is worth considering the mania Orthodox have about consistency. The church is essentially conservative to the extreme, but I believe that is the essence of preserving the received Faith.
Somewhere in the liturgical cycle, everything essential about the Faith is expressed clearly. To be a theologian is to be a person of prayer. The Faithful are continually re-catechised in this process, which is one good reason to encourage the participation in Vespers and Orthros (LOTH, in other words). One possible way to damage the orthodoxy of the community is to neglect or suppress these, so every attempt is made to sustain the practices, even in the smallest of communities.
Peace, and all good things*
Michael*