Help!!!

You have to go into assuming that your new dog was never potty trained or lived outside long enough to forget. Start with step one like you would a new puppy, be consistant, potty training doesn't happen over night. When ever he goes outside reward him heavily, make sure he know's how much of a awesome thing it is to go outside and that going outside means good things happen.
As others have said, don't rub his nose in it. He doesn't understand why your doing it or that he did anything wrong. And I'm sure he doesn't appreciate having his nose and face rubbed in a accident because he didn't know any better.
If you haven't already take him to the vets to make sure he is medicly sound and theres nothing going on.
Crate training can take time even for dogs who have never lived outside on their own, let alone a dog who may have never lived inside. Some take right to it, others need a bit of time to be comfortable with it. You can also try a exercise pen, he may feel a bit more comfortable with it since it may not feel as confining as a crate. Everything in your house is very new to him and in some cases may be brand new. Give him time and patience to learn what living with you and living in a house is like.
Also again as others have said, make sure you are cleaning with a enzymatic cleaner (natures miracle is a good brand), even if you clean it really well and you cant smell or see it anymore your dog still can.
You said he's a chewer, does he have plenty of appropriate chew toys to chew on?