To Import Levels
From the Level Manager dialog, Levels menu, choose Import.
The Import Levels dialog opens. This is a standard file selection dialog.
Select the DGN containing the levels to import.
You can import only ".dgn", ".dgnlib", ".csv", ".dwg" and ".dxf" files.
The Level/Filter Import dialog opens.
Select the levels to import and click OK.
The levels are imported into the open DGN file.