After watching the opening intro/cutscene which gives background to the story you will begin in the Great Hall of Himuro mansion as Mafuyu Hinasaki, brother of Miku Hinasaki who you will play as in Night 1 onwards. Mafuyu has gone in search of a novelist called Junsei Takamine who has gone missing whilst researching rituals of the area for a new book. Himuro mansion (also called the House of Mutilation, you'll see why later) is an old Japanese mansion which has been empty for many years and has fallen into disrepair. It had been empty since the lord of the house went mad and killed everyone in the mansion before killing himself (again you'll learn more about this later) and the Munakata family (Ryozo, Yae and Mikoto) suffered several tragedies after Yae killed herself and Ryozo was killed by Kirie (you'll see these later), it is said to be haunted and local villagers warn people not to go there as whoever goes there never comes back and that the mansion is evil.
As soon as you take control of Mafuyu turn left and head to the damaged lattice and you will see a body covered with a cloth, notice the light in the bottom-right corner of the screen (called the Filament) is shining blue, this means there's a hidden ghost in the area. Aim at the body and a blue ring should appear in the camera viewfinder, take a picture and you have just captured your first hidden ghost! The filament is one of you're most useful tools (except in Fatal/Nightmare mode where it's removed), it tells you where the ghosts are, so you don't have to rely on sensing them. When the filament shines blue it means your looking at a hidden ghost, a clue or a Talisman (which wont be encountered until Night 1), hidden ghosts are like what you just took a picture of, they cannot be seen with the naked eye and can only be found by looking through the camera's viewfinder and looking in the area where the filament tells you where it is.
Head the way you were facing and climb the stairs into the larger room, in the back corner on your right you will see something shining, this is a pick-up, which are dotted about and can be anything from health items, film, diaries, journals and so on. This pick-up is Type 14 film, which is the weakest in the game but good for early hostile ghosts, vanishing ghosts, hidden ghosts and clues/talismans. Your first playthrough will only let you have 30 shots of Type 14 (later playthroughs let you have more) but there's an unlimited supply of Type 14 in save points.
Head the back corner on the left side of the room and you'll see a camera on a pedestal, this is a save point and can obviously be used to save your game but can also be used to restock on Type 14 film. Save your game if you want.
Head through the door on your left and you now be in the Rope Hallway, as its name suggests this is a hallway with ropes hanging from the rafters. Up above a body of an unknown Rope Shrine Maiden is entombed in the rafters. At the end of the corridor is a large mirror. Move forward and the filament will glow orange and a ghost will appear at the end of the corridor, this is a vanishing ghost (called RopeHallwayMan). Vanishing ghosts are full-body apparitions which only appear for several seconds (though some are quicker than that) so if you see one take a photo of it pronto! It is extremely unlikely (well almost impossible) you will get all vanishing ghosts on your first playthrough, it can take several playthroughs to get them all.
After taking a photo of the vanishing ghost head the way the ghost was walking, head to the end of the corridor and turn right, you will see a door, go through this door and you will be in the Fireplace Room. Head to around halfway across the room and another vanishing ghost will appear (this one is ManLookingDown), this time on the balcony upstairs looking down at you. You may notice this is the same ghost you took a photo of back in the Rope Hallway.
Head towards the clock and the filament will shine blue again, this hidden ghost is in the area of the book shelfs in the small room on your right.
Once you've finished with that ghost head up the stairs and walk along the upstairs balcony thing and pick up the item on the floor. This will trigger a cutscene in which you first set eyes on Kirie Himuro and has Bound Man flying at you. Bound Man is the first hostile ghost you encounter in the game, hostile ghosts cause the filament to glow orange and as the name suggests attack you and try to kill you. Hostile ghosts appear throughout the game and can be either scripted or be random encounters.
Since this is the first ghost fight in the game Bound Man has shockingly low health, for max damage wait for the blue ring in the viewfinder to turn orange, this means the ghost is attacking and let you get more damage.
Once Bound Man is beaten head downstairs, another vanshing ghost will appear and will walkthrough the door you have to go through. Head through the door and go to the big mirror in the Rope Hallway. This was trigger a cutscene in which Kirie Himuro kidnaps Mafuyu and Miku enters the mansion a week later in search of him, Night 0/Intro is complete.