You should define how you want them to behave. You should define how you want them to interact with each other.
And you should be an exemplar of these behaviours that you define.
Every single day.
Your team will see what you do. They’ll watch how you behave.
They’ll mirror your behaviour and actions.
And if someone in your team behaves differently, address it immediately. Guide them back to the desired behaviours. If you don’t, people might start mirroring these deviations instead.
So if you want your team to exhibit certain behaviours, be an exemplar of these behaviours. And don’t allow anything less from others.