The first discovered access point was at the Witch Light Hermitage where Nadiaya was the caretaker. The heroes escape their pending doom my navigating the access point and entering the postal room.
The room looks like a large empty cavern, on the area they stood on, other area in the cavern illuminated. These illuminated areas where either next to where they were or far away.
The heroes discovered that if they walked into the illuminated areas and be teleported to somewhere else.