What are the steps to convert a single family home to duplex?

[Anne-Marie Tustin]

I am looking to purchase a single family home which has 2 bedrooms, kitchen, living area, bathroom on main floor. The upstairs has a separate entrance, then 2 bedrooms, kitchen, living area and bathroom plus a door going out to a balcony from the kitchen. Other homes on the street are multi family. I am wondering if I would need to put in a fire escape, and what other steps other than going to township would I need to consider?