File > New Scene

Clears the current scene and starts a new one. Maya gives you the chance to save the current scene before clearing it.

File > New Scene >

Enable Default Scene: Turning on this option allows you to select a file to be loaded into the scene whenever a new scene is created.
Default scene: Click the folder (browse) icon and select a Maya file.

Default Working Units

You can specify default working units for new scenes: linear units, angular units, and time settings.

The units in your preferences (Window > Settings/Preferences > Preferences) relate only to the current scene; you can change your current scene units without changing the default new scene units.

If you select Enable Default Scene in the File > New Scene options, the Default Working Units option is not available since the value of the working units is set by the default scene.

The units you specify are not overwritten when you open a scene file with different units. The first time you run Maya, the Default Working Units are set from the Working Unit values in your preferences.

For more information, see Settings preferences.

Default Time Slider Settings

You can set the default Time Slider settings for new scenes here.

For more information, see Time Slider preferences.