-( Story related, cannot be missed )-
Your introduction to one of the main elements of the game is when you're around the crime scene that is your body. You will be able to gather clues and hints surrounding your death, and it is actually required for you to finish this investigation (and primarily all others that come your way outside of the side-quests). (Direct information has been omitted at this time) By the time you solve this, you will be given access to the Apartments area and must continue the game on from there.