The altar appears in the form of a small bed in the corner of the room.

This means that the room is ready for The Sacrifice.

The Sacrifice must lie naked in the bed. No-one else, only The Sacrifice. 

The Sacrifice will fall into a deep, dreamless sleep.

Do not leave the room whilst the altar is visible.

If you do not place The Sacrifice upon the altar, you will awaken The Master.

This MUST NOT happen.

Call me using the mirror in the bathroom if require assistance.

You know the ritual.

-Hidden in the bible.