The Navigation block is a reliable way to find your way around Moodle.
Site Home is the entry page for all of Moodle.
Dashboard lists the courses in which you are currently enrolled and links to activities requiring attention such as ungraded assignment submissions. You can customize their Dashboard page by adding blocks such as Calendar or Upcoming Events to show deadlines and events for the classes they are teaching or taking.
Site Pages shows site wide activity.
Click Courses to show links to your current courses. This is the most convenient way to move between one course and another.