It is only natural for a puppy to seek out a quiet place to get a little shuteye or just to relax. Dogs in the wild actively seek out a cave or other form of shelter. Crate training is simply an extension of this natural instinct in which you will be substituting a well-equipped crate that is extremely comfortable.
The earlier you start crate training your Schnauzer puppy, the easier it will be for all of you. Like most other breeds, Schnauzers are intelligent and can learn this behavior quickly, provided you are willing to use the right method of training with positive reinforcement. If you attempt to train in a negative manner by yelling, scolding, or using force, this will make your dog reluctant to go in the crate.
The intent of this training is to teach your dog that the crate sitting in the corner of the living room is his "den" and only his. Once he figures out that the crate is his private domain, you may find you have a hard time getting him out of it. Be prepared, it is going to take a lot of time and effort on both of your parts if you want your pup to master the fine art of staying in his crate.
In the wild, a dog will seek out a cave or pile of downed trees where he can get out of the weather, sleep safely at night, even raise a family. A domesticated dog may still have this instinctual need, but since he lives in a house, the need for shelter is minimized. It falls on you to take this natural instinct and bring it back to the forefront, while at the same time teaching him the crate sitting in the living room is his den.
The most important part of crate training your Schnauzer pup is to buy the right size crate for him. Bear in mind your pup needs room to stand up, turn around, and lie down but not have enough extra space to use part of the crate as a potty area. While you don't want him to have too much room, when he grows up, he is going to need more space than he does now. Plan ahead by choosing a crate that can be partitioned to a smaller size for the puppy months, or be prepared to buy a small crate now and a larger one as your dog grows.
You need to make the crate as comfortable as possible for your pup. Cover the floor with carpeting, add a nice comfortable bed, maybe a blanket, and of course a few new toys for your pup to play with and chew on. You are also going to need plenty of nice smelly treats to help with the training and to give your pup as rewards.