First time visiting mumbai need help please

Its my first time visiting mumbai and i dont know what all to do on my first day. On my second day my friends will come but idk how to pass the time on day one of arrival. I am staying in andheri east close to the airport so i have zero idea even how to use the local or where to go or whats good. Any tips or suggestions especially recommendations would be heavily appreciated on how i can spend my day and about food.