Help > Authoring > Using Markup > Using Entities > File Entities > Creating File Entities > Using a Document
  
Using a Document
1. From within an open document, Choose Entities > File to open the File Entities dialog box.
2. Click the New button to open the New file entity dialog box.
3. In the Name text box, enter a name for the file entity.
4. Select the file:
◦ Browse to select an existing file or provide the path and file name in the File name box if this file entity will only be used for this document.
◦ Public IDs are used only if the entity is likely to be used by other documents. In order to use a public ID, you must first add one to your catalog file. You can also browse to select a file entity that has already been listed in your catalog file and assigned a public ID.
5. Click OK. The entity will become available when you close the File entity dialog box