First, make sure your puppy is comfortable wearing a leash. This can feel strange at first, and some puppies may bite the leash. Give your puppy treats as you put the leash on each time. Then, stand next to your puppy with the leash in a loose loop and give him several treats in a row for standing or sitting next to your leg. Take one step forward and encourage him to follow by giving another treat as he catches up.
Any area that the pup has access to must be kept clear and clean. Put out of puppy's reach anything you don't want him to chew or destroy. Do not allow your puppy to have unsupervised access to 'unchewables.' Do not chase the puppy in an attempt to take something away. Instead provide puppy with her own toys and teach her how to play with them exclusively.