Evenly distribute or scatter the tombstones and the candle/votive holders on the mantel shelve. Place the lantern in the centre and the tree branches filled vase close to it.
Sit the baby zombie in front of the fireplace or even on a chair beside it.
Drape the ghost onto the backrest of the chair.
Place the pumpkin on the coffee table or anywheres for that matter. Really, you can add as many pumpkins as you desire. Just make sure to balance them out uniformly around the room.
Most of these items can be found in a dollar store, thrift store or you most likely already own them. Happy Halloween!