To Create a DGN File and Open It

Do one of the following:

From the Work page, click New File.

or
From the ribbon, choose File > New.

The New dialog opens.

The default file filter is "MicroStation DGN Files [*.dgn]." The file specification for the default seed DGN file displays in the Seed field.
(Optional) To change the filter, choose the corresponding item in the Save as type option menu.
(Optional) To select a different seed DGN file, click the Browse 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 Save in option menu.
In the File name field, key in a name for the new DGN 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.

Although the extension ".dgn" is often used to indicate a MicroStation DGN file, any extension (or no extension) is acceptable.
Click Save.