My grandmother(Guardian Parent) has passed and named me the beneficiary of her estate on the other side of the country. Who do I contact first?

My grandmother has passed away on December 10th, and the women living with her had not informed anyone until recently, So I have just found out about this. My grandmother is my Guardian parent since I was 5 and has named me the beneficiary of her properties, she was living in California when she passed and I am on the East Coast. My biological mother has been using my grandmothers vehicle and credit card and living in the home since the passing, but the will states the property is now mine and I need help getting her out and handling the property.