When a young dog is left unattended inside or outside, he will find a way to entertain himself. Leave chew toys and such lying around so your pup may entertain himself when you're not available to play him. If your dog still insists on digging, try giving him his own area, and put toys and treats in the ground, so that he will become accustomed to digging in that main area.
Your puppy's training is all in your hands. Training a dog to become how you want him to be is not an easy task, but could become even harder if one is not committed. It takes time, effort, and attention! There will be days when things seem like they could not go any worse, but trust me. Things will begin to improve. A puppy is just like a child, with the right tools, attitude, and commitment it can be done.