Before i begin I will like to clarify I am not here to look down upon other people's spiritual practices because there is still a lot of things science does not know. I am here to share my opinion and that's it. So please do not leave any nasty comments.
Now lets begin...
Many feel that the Ouija board is done through aims of spirits talking through the board. Though this is true to some people, it is not true to skeptics who have see it done far differently. The Ouija board is not a gateway to the spirit world, but rather a gateway to the unconscious. The unconscious is place where we store information about people, various kinds of knowledge, memories, or even about our surroundings. Whatever is in the unconscious is something that we are not conscious or in other words not aware of at that moment. When we are talking to "spirits" with it we are actually talking to ourselves through our own psyche. But lets not get to ahead of ourselves. How does the planchette move by itself then?
With that said, the main reason of how the planchette moves correlates with the Ideometer effect. The Ideometer effect tells us that when the planchette moves we are not consciously aware that we are moving it ourselves. These movements are so subtle that we don't feel them because our unconscious mind directs it.
When we talk to spirits most of the time it is information we already know but forgotten in the unconscious mind. Such as the predicament in World War II. With all the loss of soldiers at battle during this era people took comfort with to call upon their dead loved ones with the board. Though not knowing the spirit of their loved one was only giving them knowledge that appeared to be genuine but instead fabricated by their psyche.
If someone believes in something it hold power over them and can manifest as something similar like with those dead soldiers. If a Christian did so and wanted to talk to their dead relative who was also a Christian, then the will get a Christian like response. Such as them being in heaven or at peace. This goes with any other religion or belief system the person may have. But if there were any doubt within their mind about something negative then expect a negative response. This doubt does not need to be something they are consciously aware of, but could be unconsciously as well.
Another thing to note besides all the stories you heard of a deceased loved one who died before you were born, all you would get out of contacting them will be somewhat of a fabrication of those stories you have held in your psyche. People you didn't know will just give off something made up from your own mind. Whether it be positive or negative response will be up to your unconscious or conscious mind.
If you are somewhat afraid of the Ouija board, I would not recommend using it because you will most likely get a negative response to your questions. These negative responses can even come from the unconscious mindif you are not consciously afraid of them. These evil spirits are just manifestions of your own mind tricking you and should not be taking seriously. Anything your afraid of puts yourself at their mercy, which in return and scare you even more.
How, can someone use this in a occult fashion though you make ask? Lets say I wanted to contact a dead relative because I need some knowledge from him/her or maybeI just want to talk. All the information or data you have from this person you knew in life accumulates a strong connection from all the memories or knowledge you have of that person. Thus giving off something to work with in your inner psyche. When you ask them questions they only know the answers from the response of your own mind. This can come in handy if you wanted to know something you have forgotten, like where they hidsomething or any kind of juicy secrets,you knew consciously but have forgotten.
You can make this into a elaborate ritual or something as simple as possible. This is my beliefs systems on how the Ouija board works according to science. I hope you liked this post and I hope you have a great day.