The help system should be used as a secondary mechanism to support users’ complete and better understanding of tasks — the primary mechanism should be the user interface itself. Users consult the help system only if they can't accomplish a task with the UI.
Try to make Help unnecessary in the first place:
- Make common tasks easy to discover and perform.
- Provide clear main instructions as well as concise control labels that are goal- and task-oriented.
- Provide supplemental instructions and explanations where needed.
- Avoid problems by using controls constrained to valid choices, providing suitable default values, handling all input formats, and preventing errors.
- Write error messages that provide a clear solution or action for the user to take.
- Usually, the help system is activated by F1 respectively Ctrl+F1 for context sensitive information and via menu.