What happens is that Harry finds in there is some strange looking machines. We find that the machines do different thing but that all are not working. He looks and sees that most only need to have a circuit board installed. He had found his fathers notebooks with the info what each of the machines are suppose to work.
He reads that one of the machines is to make a person change there age, the next is to swap bodies with someone else, the next will let you swap different parts with someone else, etc.....