How would anarchism work, in practice?

Anarchism “is a political philosophy which considers the state undesirable, unnecessary and harmful, and instead promotes a stateless society, or anarchy.”

That sounds fine and dandy in theory, but how would that work in practice? Say we get rid of the government, so now there’s no police. What would stop me from going around stabbing people, stealing and whatnot? If there’s a small group of people in charge of that, wouldn’t they be some kind of de facto government?

What do y’all think?