To Copy a Template Group

In the Element Templates dialog ( Drawing > Home > Attributes > Element Template > Manage ), select the open DGN file.
(Optional) If the template group you are copying is from a DGN library, expand the DGN library.
Select the template group that you want to copy.
Do one of the following:

Click the Copy icon.

or
Right-click the template group and select Copy from the pop-up menu.
Select the open DGN file or the template group to which you are copying the template group.
Do one of the following:

Click the Paste icon.

or
Right-click the location to which you want to copy the template group and select Paste from the pop-up menu.