Crates are a great tool, to provide your dog with a safe, puppy-proofed environment, safe spot to hide from unwanted guests and to sleep undisturbed.
A crate should be big enough, so your dog can stand up and turn around comfortably, space for food and water bowls but also small enough where they won’t have room to toilet away from their bed. Soft bedding should be placed on the bottom, so your dog can rest comfortably.
Puppies age 8-10 weeks should not spend more than 30-60 minutes at a time in a crate; 11-14 weeks 1-3 hours; 15-16 weeks 4 hours, 17+ weeks 5 hours.
Once you buy a crate, leave it with doors open for a few days, so your dog has enough time to inspect it on his own. If you see your dog investigating the crate, praise him or give some treats for the curious behaviour.
Before and after crating for the night, your dog should get at least 30 minutes of physical exercise.
Move from one step to the next step only if your dog is calm and relaxed. Do not rush. Remember that crate is a safe paradise for your dog and never should be used as a punishment tool.
Do not crate your dog only when you leave home, so your dog does not associate your absence with the crate. When you are at home provide some random time periods of crating.
Do not act excited when the dog leaves the crate, this should be no big deal. Be neutral in your body language.