Unless you plan to keep your dog outdoors--and few of us do because it's not recommended--you'll need to teach your dog where to eliminate. Therefore, house training (also called housebreaking or potty training) is one of the first things you need to work on with your dog. Crate training can be a very helpful part of the training process. This includes house training as well as many other areas of training:
Choose a well-ventilated crate that is large enough for your puppy to stand up, lie down, and turn around. Remember that your puppy’s crate will have to grow as he does, so purchase a crate that is appropriate for your dog’s expected full-grown size, and use a divider to make the crate smaller for the time being. Many crates available at pet-supply stores include dividers.
“Down” can be taught very similarly to “sit.” You can wait for your dog to lie down (beginning in a boring, small room such as a bathroom can help) and capture the behavior by reinforcing your dog with a treat when he lies down, giving him his release cue to stand back up (and encouragement with a lure if needed) and then waiting for him to lie down again. When he is quickly lying down after standing up, you can begin saying “down” right before he does so.