Good point. The church in Jerusalem never issued guidance. Except when they did.
But churches SHOULD interact and support - or rebuke - each other.
Got to it before me. The Council of Jerusalem is the obvious earliest recorded example. Clear direction to *all* churches on how to handle the fact that both Gentiles and Jews are in the Church.
The Church in Jerusalem. The Jerusalem Council as it's sometimes called. So why did Paul go to Jerusalem in Acts 15? Well, verse 1 tells us certain people (troublemakers) came to Antioch from Jerusalem and began a conflict with Paul and Barnabas.
So they and others naturally went to Jerusalem to meet with the elders there in order to resolve the conflict. The elders there solved the problem and sent instructions much in the same way Paul and other apostles sent instructions to independent churches.
But Acts 15 in no way set or established a standing headquarters or a permanent authority structure over any other churches.
Any denomination that uses Acts 15 as a guideline for a hierarchy is in error.