What constitutes disruptive behaviour in young kids is very subjective. However, by looking deeper at your childs behaviour it will help you understand more about why they act in a certain way. Behaviour that can appear naughty or disruptive to you, is often just your childs way of communicating an unmet need as they try to figure out their way in the world.
Teaching babies the difference between day and night can be a bit of a challenge until their body clock kicks in. However it's something you can easily help them learn from just a few weeks old. Whilst its not possible to establish a routine when your baby is very young, there are things you can do to separate day and night activities. In the long run it will also mean you will both start to get more sleep.