Dogs that appear uncomfortable getting into a crate can be desensitized by dis-assembling the crate and beginning the training with out the top in place



Begin by just clicking the beginning phases of the behavior and by delaying the click you get more from the dog. Don't delay too long dogs have a shorter attention span than children. Once you consistently see the behavior you can then name it and add the cue you want to use.



There is additional information on the page "home alone"