You can access your Classroom once you log into your account or directly from https://classroom.udacity.com/. On the left hand side of your Classroom is your navigation menu. Here you will find the navigation links to access your help services, as well as your account settings.
If you’re enrolled in multiple Nanodegree programs, you will see all the programs you are enrolled in on your Classroom homepage. From the homepage, you have the ability to select which Nanodegree program you want to work on and also access any Nanodegree programs you have already graduated from.
Once inside the Classroom for a specific Nanodegree program, you can navigate anywhere within a lesson from the menu on the left side of your screen. If you don't see this menu, click the three horizontal bars at the top left of any page to display the menu. To navigate to a different lesson, click the lesson title at the top of the navigation menu. This will take you to the Syllabus view, and from there you can navigate to anywhere within your course or Nanodegree program.