The Symbols dialog lets you browse SmartDraw's entire symbol collection. Symbols are organized in logical groupings called libraries. These libraries are then contained in categories similar to SmartDraw's template browser.
To expand a category like Certificates or Clip Art click on the category name or the folder icon.
You'll get a list of libraries in that category. Click on any library name to display a preview of the symbols inside that library. Click "Add Library" to add that library to your drawing's SmartPanel.