Cover the entire floor with newspaper so that no matter where he "pottys," he will hit paper. After a few days, gradually take up some of the paper (leaving the paper nearest the door with a puppy pad) so that as the puppy walks toward the paper you get the cue that it's time to take him out. A child's gate and some puppy pads combined with a consistent catch phrase ("potty time"... "wee wee" ... etc.) that your puppy can understand will be the most important tools you can use. And always use the same door and take your puppy to the same location to potty. This will let him know exactly what you are expecting him to do so you don't find yourself standing out there forever ... waiting. Go out another door for every other activity. The puppy pads are great because now that your puppy has been using one in the confined area you can put one on a drop cloth or vinyl table cloth in the carpeted area where you are watching TV or whatever, so he will have an emergency place to go when he is with you.
And one last thought. You've probably heard that it does no good to "rub their noses in it." Well, believe it! This only confuses the pup and can result in extending the time you spend housetraining your pet. Spanking is also a poor response.
When your puppy has had an accident, remember it is just that, an accident. Puppies are not spiteful or malicious. You wouldn't spank a toddler for wetting the bed. Puppies are much like babies. Take the same approach with your puppy that you would take with your toddler. Pick him up and run for the "potty" which in this case is the great outdoors and ask him if he can potty more in the grass this time. Praise him, letting him know that he has done something really good when he uses his "potty" and then do everything in your power to reinforce the idea by getting him out there so often that he has little opportunity to have an accident in the house. Remember, animals are creatures of habit. It takes about 2 weeks to establish a habit so make sure that you are willing to invest the time in the first 2 weeks to establish the right habit.
And let your puppy do things because he knows you'll love him for it ... not because he is afraid you'll hit him if he doesn't. Keep in mind that you are the being with the higher intellect so it is your responsibility to help him learn without hurting him ... physically or emotionally.
We hope this will help you make housetraining a more enjoyable and healthy experience for both of you.