In the last lesson we recommended that you save your work at regular intervals. An example of this is when you have just completed a major task such as constructing the base for the temple. With this strategy, if you ever make a mistake, you can always open the previously saved version of your work and begin from there.
A file browser appears showing the GettingStartedMaya2013LessonData\Basics\scenes directory where you can save your scene. Ensure that you are saving in the scenes sub-directory.
If the GettingStartedMaya2013LessonData\Basics directory does not appear, you need to create the Basics folder and set it as your Maya project. See Downloading the lesson files and setting the Maya project.