The same way I govern my family. By talking to people, finding out what actions we can all not worry about, and what actions may put someone else in a bad position, and work with them to find wyas of alleviating friction. 'Some ass in the back' sounds like you're referring to someone being aggressive. First, you ask what has spurred the action, and see if it's something that can be addressed diplomatically. If not, actions can be taken to either defend, or extract justice. How communities decide to hold court is for them to decide. As for punishments, I'm not a hig fan of prison. Service to repay debts can work, and outlawry when it can't. Iceland held court for centuries without any executive body; there's plenty to be learned from there.

The issue people tend to have with anarchism tends to be some desire to control and define every facet of governance and life in some utopian ideal, despite no system that does involves government ever actually operating along some robotic algorithm in this manner. I don't have a utopian idea to strive to. I have a principle of non-aggression which I aim to see implemented when it can, where it can, and how it can be. As with most things in life, the perfect is the enemy of the good. There will always be places where someone exercises power in a way that will not be perfectly justified, either because there is a need to act more quickly than communication will allow, because of heated emotions, or other circumstances beyond our control. What matters is how we bring things back to harmony after the fact, and look to improve moving forward. A community is like a marriage, but with a lot more people. Force is not the best medicine.