To start a new, blank scene file
You can select to always create new scenes with default content by choosing File > New Scene > and turning on Enable Default Scene.
To open an existing scene file
The Open dialog box appears, open in the scene folder of the current project.
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.