Take your roo, put him in the coop with plenty of food and water, and keep him there for 3 or 4 days. Then let him out during the day. Physically place him in the coop every night until he gets the idea - you can also lure him into the coop each night with food treats - best tip I ever got was to train the chickens to come running at the sound of a shake of a treat can.
when you get the hens, they will also need to be shut into the coop for a couple of days before being let out so that they learn this is their home. If you let them out right away, it is harder to get them to learn to come in at night. Assuming you want them in at night - usually a good idea because of weather, predators, etc.