Your dog should be able to stand, sit up, turn around, and lie down comfortably in his crate a dog instinctively avoids eliminating in the area where he sleeps or eats. If a crate is too big, he may eliminate in it.
Make sure the crate is a safe haven for him. Do not punish him in it.
Whenever you let your pup out of the crate take him outside. Learn his "prepotty" behaviors, such as circling, holding his tail a certain way, or sniffing. When you see these behaviours, immediately say "potty" so he associates that word with what he is doing and will do it on command in the future.
If you let him out of the crate inside the house, keep close tabs on him. If you see pre potty behavior, make a sharp noise to stop the flow and immediately take him outside. Praise him softly as he goes. Once he is finished, praise him more excitedly. Give him a treat or play with him so he associates going outside with something positive.
Be consistent and patient. Accidents are bound to happen, so make sure you have cleaning products on hand.