To Create and Open a New DWG File

From the ribbon, choose File > New.
The New dialog opens.

The default filter is MicroStation DGN Files [*.dgn].

The file specification for the default seed DGN file is displayed in the Seed field.
Change the filter to AutoCAD Drawing Files [*.dwg] under the File Type option menu.
The Seed field now displays a seed DWG file.
(Optional) To select a different seed DWG file, click the Select button and use the Select Seed File dialog.
(Optional) To select a different destination disk drive or directory, choose the desired drive or directory from the Look in option menu.
In the File name field, key in a name for the new DWG file.
The file list is useful for ensuring that the new filename is not that of an existing file, or for selecting an existing filename and amending it.
Click Save.
The new DWG file opens. It uses the settings defined in the DWG seed file. Note that the DWG file symbol appears in the status bar at the bottom right of the program window.