Helpful but not absolutely necessary:
Start in a quiet room near family. Your dog should be part of the family. The crate should not be isolating.
Practice the above steps a minimum of 3-5 minutes, 2-3 times per day.
Consider practicing at mealtimes until your dog is eating the crate.
Your dog should be happy to spend time in his crate with the door closed.
My dog is whining. Consider if your dog is truly in distress by checking his/her body language. This can be challenging, but it’s important that your dog not be traumatized by being locked up. If your dog is truly in distress, let him/her out. If your dog is simply being demanding, you can ignore the vocalizations. Be careful that your dog does not try to break himself out of the crate! A distressed dog can injure him/herself trying to free itself!
My dog refuses to go near the crate no matter what I do. Your dog may truly be afraid of confinement. In this case, consider a hallway or quiet space where your dog can relax when you need time to yourself. Not all dogs enjoy being crated, but most do.