From LibreOffice Help
|Use the Add to Bookmarks icon to set a bookmark for the current page shown in the Help.|
You can find the bookmarks on the Bookmarks tab page.
Double-clicking a bookmark or pressing the Return key opens the assigned page in Help. A right-click opens the context menu.
- Use the Del key to delete a selected bookmark.
The following commands are on the context menu of a bookmark:
Display - displays the selected help subject.
Rename - opens a dialog for entering another name for the bookmark.
Delete - deletes the bookmark selected .