Link controls enable you to provide more navigation in topics. There are three different kinds of link controls that you can create, including:
Related topics: Related topics help users navigate among related concepts in topics. A related topics link is a control that displays a list of related HTML topics that users can go to.
Keyword links: Keyword links enable users to find topics based on the keywords they reference. A keyword link is a control that displays a list of HTML topics that are based on keywords in your index.
ALinks: ALinks provide a way for users to find topics that are grouped into categories. An ALink is a control that displays a list of HTML topics that are based on ALink names assigned to topics in your project. The ALink names you assign group topics into categories.