Want to take possession of my Flat

The registry of the flat is in my name in Partition Deed made by my Grand Mother, she gives one Shop to my youngest brother and also another Flat is in my Father's name in the same Partition Deed currently I am living in the Flat which is in My Father's name with my another brother. We are three brothers. My father died few months back and there is no will for that flat which is in my Father's name and my youngest brother is living in the flat which is in my name with my mother and i want to shift in that flat which is in my name with my family including my mother. What can i do legally and also can i get my 1/4th share from the flat which is in my Father's name. Please advice....Thanks