What legalities should I be careful when moving in as a flatmate?

I [22M] an new to Gurgaon, working at in a new office where I made friends another new joinee [22M]. We have a lot of shared interests and generally got a good vibe together, talking over meals. He's scouted out a 2BHK apartment and needed a flatmate so I said I was interested. However, I have never lived in a shared flat like this before and want to avoid the sort if horror stories that I've heard here. We went over and looked at the apartment together, it is spacious, affordable, and close to the office. We also have matching eating habits and are health conscious. I really want to get this apartment but my friend is in direct contact with the brokers and doing all the formalities. What sort of legalities should I be careful of begore moving in?