My 12 week old puppy soils all around the house, even after taking him for a walk. He will do nothing then chooses to defecate inside. Does anyone know how to stop this?

He's a puppy, so you can't expect him to be toilet trained. Take him out periodically, after play, after food, after drink, when he wakes up, once an hour (even if he's been out multiple times throughout that hour), in the morning when he wakes up and in the evening before you go to bed.

Clean up any messes you make!

Don't make a big fuss of the indoor messes, but praise him like he's the cleverest dog in the world when he does it outdoors.

It sounds great!How's everything?