There are basically just a few steps and rules in crate training:

1. Choose a crate the same size as your puppy/dog. They should only have enough room to stand up, turn around and lie down. Their crate is for sleeping or for a safe place to be when you cannot be with them. If you have a large breed puppy, you may have to buy two different size crates or purchase a crate with a divider you can move as they grow.
2. Use a single-word command for your dog to enter their crate and throw in a piece of kibble (dog food) or their favorite treat. When they enter, praise them and close the crate door. Wait a few minutes and let them out, and do it again. Gradually increasing the time they spend in the crate before you let them out. Do not give treats or food as a reward when they come out. Only reward when they go in.
3. Remember, your dog still needs time to play and eliminate. Maintain a regular schedule of trips outdoors and don't confine them too long. Puppies bladders are very small and not fully developed in their ability to hold it, so they need more frequent trips outside, than an older dog.
4. As a general guide, your puppy can stay in a crate, comfortably, for several hours, depending on their age. Take their age in months, add 1, and that’s how many hours they should be able to stay comfortably in a crate (up to about 8 hours). For example, a 2-month old puppy should be comfortable in a crate for about 3 hours.
5. Providing your dog or puppy with a crate that is way too large may allow them to relieve themselves in one end and sleep in the other. Placing food or water in the crate will allow them to fill up their bladder and bowel and they will have no choice but to relieve themselves in the crate.
6. Make sure you take your dog or puppy outdoors to eliminate on a regular schedule and especially prior to being left for prolonged periods of time. Always take your dog outside on a leash to the same area in your backyard to eliminate so you can praise them when the job is finished.