Red beans and rice

Ingredients: 1 pound dried red beans 1 tablespoon olive oil 1 large onion, chopped 1 green bell pepper, chopped 2 celery stalks, chopped 4 cloves garlic, minced 1 pound smoked sausage or andouille sausage, sliced 1 ham hock or 1 cup diced ham (optional) 4 cups chicken broth 4 cups water