Doing something peaceably means acting in a calm, nonviolent way. You might describe a group of protesters as standing peaceably in front of City Hall, singing and chanting and they lobby for change.
Generally, peaceably can be used as a synonym for "peacefully," at least when you're describing people or groups of people as acting peaceably (you probably wouldn't say a bird sang peaceably, for example). Behaving peaceably means you're actively encouraging peace rather than conflict. In your dense neighborhood, it may require some compromise and understanding to live together peaceably.