To Add a Template

In the Element Templates dialog ( Drawing > Home > Attributes > Element Template > Manage ), select the open DGN file.
Select the template group into which you want to add the template.
Do one of the following:

Click the New Template icon.

or
Right-click the open DGN file and select New Template from the pop-up menu.

A new template appears with the name "New Template."
Type a name for the new template.