The initiator is the person that identifies an organizational problem and requests the purchase of a product or service that will solve it. In other words, the initiator identifies the unsatisfied need and starts the buying process.
The initiator doesn't have to be the user of the product or service that is being requested. E.g. in this case, the president of the student body may or may not use the computers in the main computer lab.
If two sides of a rectangle add up to 18cm and the area is 80 units squared then the length is 10cm, and the width is 8cm. If you add 10 and 8 together you get 18, and if you multiply those you get 80 units squared.
