Some help requests amount to an explicit request for specific information, such as help on "version" (which usually displays the copyright topic). Other help requests, however, may require some degree of context sensitivity. That is, some processing might be needed to determine the appropriate help topic based on the user's current context within the application.
For instance, your application might test the status of certain modes or settings to determine the appropriate help topic. Or, it might test the value of an input field and provide detailed help if the value is not valid, and general help if the value is valid.
An entry point is a specific location within a help volume--usually the beginning of a topic--that can be directly accessed by requesting help within the application.
From the author's point of view, entry points are established by assigning IDs at the appropriate places within the help volume. From the programmer's point of view, entry points are created by enabling the user to request help and using the appropriate ID when a particular request is made.
There are four general ways for users to request help:
Pressing the help key (which is F1 on most keyboards)
Clicking the Help button in a dialog box
Choosing a command from the application's Help menu
Choosing On Item help