The XML file you want to assign a DTD to should be open in the active document window.
On the DTD/Schema menu, click Assign DTD
to XML File.
The
Assign DTD
dialogue box is displayed.
Select the DTD file you want to assign and click Open.
If the DTD is valid the Select Root Element dialogue
box is displayed.
Select a root element and click OK.
The
DOCTYPE declaration
is placed in the XML file.