Crate training is pretty straight forward. At night when its time for bed, put your dog in the crate. Make sure the crate isn't too big or too small. Your dog should be able to turn around comfortably. You can also throw a safe toy in there for good measure. Dogs will not soil themselves in their crates. Its a natural instinct of theirs not to dirty their sleeping place. A crate isn't cruel either, dogs are den animals, so the crate makes them feel right at home. Just make sure they don't stay in their crates for unusual amounts of time.
When your dog isn't in the crate when you're at home, the bell technique is perfect. The bell technique consists of hanging a christmas-like bell from the door (knob) you always let your dog out, at nose height. The first few weeks you have your dog, you MUST keep your eyes on him/her like a hawk. It's imperative to catch your dog in the act of going to the bathroom indoors. A stern, "NO" will do, quickly walk the dog to the designated door and manually hit the bell with his/her nose and say, "outside." You MUST be routine with this step. After a few weeks your dog will start running over to the door and hitting the bell with their nose on there own! It's also VERY important to praise your dog when they're doing their business outside with a "good boy, or good girl," in a high pitched voice. All dogs love/respond to high pitched voices! With these techniques your dog will be using the outdoor soil as their personal bathroom in no time.