Think of it this way -- you've just been placed in a foreign land -- you don't speak the language, you don't understand what's expected and a lot of new -- sometimes frightening, sometimes exciting -- experiences are ahead of you. That's a taste of what it might feel like to a dog -- be it puppy or adult -- that has just come to your house to stay, hopefully for life.
There are bound to be a few problems along the way. The thing to remember is that most problem behaviors can be rectified with patience and love. The first step is usually trying to see the world as your dog and then together you both can start to speak the same language.