To start a new, blank scene file
You can select to always create new scenes with default content by choosing Enable Default Scene in the New Scene Options.
and turning onTo open an existing scene file
The Open dialog box appears, open in the scene folder of the current project.
To open a file that was created in a earlier version of Maya, ensure the Ignore Version preference is turned on in the File/Projects preferences. See Files/Projects preferences.
To save the current scene file
When you use Save Scene As you can select whether to save the file as Maya Binary (smaller) or Maya ASCII (human readable). To save in a different format, use File > Export All.
You can optionally lock a file to prevent the file from being edited whenever it is referenced from other scene files using the Lock file option.