The ouija board is like a chess board but without the surface divided into equal squares, it can be bigger and the figures shown on the surface are letters of the alphabet and the numbers 1 to 9 and 0; there is what is called a planchette which is like an arrow head used for a pointer, which moves to letters and numbers to write a message.
That description above is just for people who don't have any idea of the ouija board.
The board is used by people -- who else but people, to make contacts with spirits, which spirits will answer questions from people using the board.
Usually at least two persons will use the board: they each touch the board lightly with one finger, and address their questions to the spirit believed to be present; the planchette will move to letters and numbers which compose an answer from the spirit.
Can we use then the ouija board as a scientific way and means to communicate with spirits, and why not?