they're not evil, but can be dangerous if you don't know what you;re doing. get some sage smudge so you can cleanse the house after using the board in case. be sure to cast a circle that's very important. store the board in a safe place so it's not damaged.
to contact a spirit just place your fingers just above the planchette [pointer thingie] not touching it, and ask if there's a spirit. you should feel your tips being attracted to the planchette, similar to holding 2 magnets slightly apart. be polite, and don't forget to thank it and say goodbye or it might linger to bug you.