First try putting him in the crate, then without any fanfare or words or anything, go out the door. IMMEDIATELY return (as if you forgot something) and again, without any fanfare, open the crate door and let the dog out. Don't coddle or coo with him or anything. Just make like it is the same as him going in on his own.
Leave ample water for the dog but not enough room for him to pee in the corners and still have room to sleep and not sleep in the mess. Also remove his collar and tags while in the crate alone and unsupervised so as to avoid an possibility of getting them caught and the dog choking.
Put some toys (safe toys, not chew bones or rawhide which needs supervision) in the crate, a shirt that smells like you in there (one you can live without), and you can leave on the tv or radio softly as well. This helps relieve anxiety.
Do this a few times, then lengthen the time you are outside the door. As you lengthen the time, make sure you do NOT go back inside if the dog is crying/whining. Wait until he is quiet and then go back inside and let him out of the crate.
As he gets used to it he will then not cry and whine since he learns that only being quiet will get you to come back home - not whining and crying.
When he's quiet as you leave and remains so while you stand outside listening, you can then begin to leave the doorway for short trips (get in the car, get out and come in again if the dog is quiet), then gradually get in the car, go out of the drive way, and back, then work up to around the block, etc., extending the time that you are gone.
Another key to successful crate training is to make SURE the dog is well exercised and tired before leaving. If that means getting up 30 minutes earlier to go exercise the dog and wear it out, then so be it. But the old addage sure is true in that a tired dog is a well behaved dog.
Good luck.
You can also do a search here at BW using the search engine and terms such as "crate training" and see the
puppy pages here at BW and click on the links on the left side of the page for more information on crate training.