Use an .html file to create introductory content that will display when a user clicks on this new catalog in the AutoCAD Civil 3D Content Browser. You can use any html editor, and the cover page can be as simple or as comprehensive as you like. Typically, the cover page gives an overview of the tools supplied in the catalog, and a brief description of how they may be used.
By convention, cover pages are named <Name> - ToolCatalogCoverPage.html where “<Name>” is the name of the new tool catalog. The location of the .html file is specified within the .atc file. This file is usually placed in the same directory as the .atc files themselves.