Division after divorce

Hello, I am a mother of 2 adults, a daughter and a son (aged 20 and 22 respectively ). I have been married since 23 years. I live a separated life in a joint family since last 6 years. My husband doesn't have any property under his name. The house in which we live was owned by both my father in law and mother in law (50% share each). After the demise of my father in law the will of the property came out in which it was mentioned that the property is divided between my brother in law's son and my son (50% property of father in law). The upper portion belongs to my son, its where we are living since his birth. And so is lower portion given to my brother in law's son. There is 50% property of my mother in law still there and she is still alive. Also, I have 2 sister in laws as well, both married since a long time. I doesn't wish to live in a house where I am seperated, so I will be filing divorce case very soon. My few questions are 1. What is the proper way to file this? 2. How much my share in the property should be? 3. If I get a share in property how can I claim that as it will be divided among 3-5 people? Will i be mandatory to sell that property?