All of my dogs are crate trained, and I’m a huge believer in crate training. All dogs are descended from Grey Wolves which are den animals. They feel safe in their dens, its their safe space to sleep, give birth, and raise their pups. Both wolves and dogs wont (assuming they are raised properly) defecate in their dens which can greatly help in house breaking.
Some dogs will immediately love their crates, these are usually the more “balanced” dogs. While others will dispose them seeing them as a scary place of confinement away from the things that comfort them. Whichever is the case if you should start the same way, but for dogs who obviously like the crate you can speed up the process. For example, Josie my first dog (and most balanced/well-adjusted dog) was crate trained in a day, whereas we’ve had Luther for over a year and he still can’t be left more than an hour and won’t go in crates other than his own.
Always start with the door off if it is removable. Put something comfy (and washable if you have a puppy) on the bottom and keep the crate around in an area the dog is often in so its just part of the environment. After a few hours (longer for more anxious/fearful dogs) toss some treats just in the door and allow the dog to go in and get them and come right back out. Repeat this several times through out the day. During this introduction time its also helpful to feed your dog his meals in his crate (Simon and Luther are still ALWAYS eating in their crates) still with the door off.
If they seem comfortable with this put the door on, but leave it open and repeat all of the above, adding the word “Crate” (or kennel or bed or whatever command you want) when they enter the crate.
Once they are happily going all the way to the back of the crate, start feeding them with the door closed, opening it as soon as they are finished. Then start sending them in the crate (always with a treat) and shut the door and leave them in for a minute or two. Let them out after the pre-determined amount of time. If they cry, let them out after they have STOPPED for 3 seconds! Just sit and wait till they calm down. If they cry, do a shorter amount of time next time. Slowly increase the time each time you do this (a few times a day, including at meals). Again, the length of each step can vary drastically from dog to dog. Some may only need to do this once, others it will take months. Most dogs should be ok in the crate for an hour within a week or two, if you do the exercises several times each day.
For overnight crating of a young puppy, I highly recommend keeping the crate next to your bed and bringing the puppy out every few hours to go potty and not giving water at night (unless it is very hot). This is what se did with Aiden for the first few weeks, till he could go 6 hours with out crying, then we put his crate in the kitchen. At 6 months old when he was fully house trained we let him sleep on a bed in our room at night, but still use the crate for a safe place while we are gone.
Crates should be a happy place for a dog, a place they WANT to go, my dogs often will just go sleep in their crates all on their own. They do this because they feel safe there and like it! Just like you feel safe and comfy in your bed! If they are feeling anxious in the crate back up a few steps and SLOW down, many rescue dogs and pet store dogs (which you should never buy, but may have already done so) are very hard to crate train because they had a bad experience with a cage in the past. Be patient and loving and keep trying!