My family just welcomed our little Trigger into our family about a month ago now. He was born on July 7th. I am trying to train him as well and last week started the bell at the door. When I am ready to take him out I say "Trigger let's go outside and go potty" and ring the bell, he will come running and then I take him out and place him in the spot I want him to relieve himself. When he is done I say "Let's go back inside" and when we get inside the door I have a treat waiting for him. He now knows about the treat because as soon as we hit the inside he turns right around and looks at me. It is so cute.
I do think I will change one thing and that is take the treat with me outside and give to him as soon as he does his thing. I think that would make him understand better.