How to make a place a tad haunted ?like actually haunted

So i hate my school and i would like to now how can i make it tobe haunted by ghost ? Or tiny demons or smt ...are there symbols i can draw that will invoque spirits or anything i can do?I thought about putting two mirors facing eachother in the school so maybe a portal would open idk you tell me.My school is not that that big its also quite ancient so maybe i could find some ghost livin there and tell them to come back .this is not satire i really wanna now how to haunt my school thank you.Also i dont want to kill anyone in the process .