The county commissioners shall meet at the time and place appointed and view the way, and there, or at a place in the vicinity, hear the parties interested. If they judge the way to be of common convenience and necessity or that any existing way shall be altered, graded or discontinued, they shall proceed to perform the duties required; make a correct return of their doings, signed by them, accompanied by an accurate plan of the way, and state in their return when it is to be done the names of the persons to whom damages are allowed, the amount allowed to each and when to be paid. When the way has been finally established and open to travel, they shall cause durable monuments to be erected at the angles thereof.