You may invite a priest or do it yourself. Use holy water, church candle, frankincense. From an entrance door go clockwise with burning candle. Lighter in a left hand. Cross all the walls and pray: Lord's prayer, Let God arise..., say: - All evil spirits get off! Glory to Father and Son and Saint Spirit!
Evil spirit will try to put out a candle, light it again and cross the place again. End at a door, open and say: Satan and all your forces, get off!
After that patiently splash the walls a holly water. Easy to use a spray bottle. Smoke a frankincense. All of that contains a part of Saint Spirit and will destroy an evil.
What to do with the souls of deads, I wrote earlier.