The HPL online help
The Help menu on the main window has Glossary and Contents choices.
The Glossary option opens a scrolling list of items. Select an item to see its definition. The Contents option takes you to the main contents page. This page directs you to discussions of various HPL topics.
If you click Help in any window other than the HPL main window, Help displays information that is related to the current window. After the Help window opens, you can click its Help button for more information about using the Help window.