@water,
To download and install the built-in help, first you need to know wich file to download. So, open LibreOffice, then choose menu Help
- About LibreOffice
and see what is your LibreOffice version and operating system.
If you copy the info (like the selected text in the previous image) and paste it in a comment, it will be easier for us to guide you in installing the built-in Help.
EDIT: Now follow this link to download the file to install the Help for offline use matching your LibreOffice version. Once downloaded, with a double-click (or select and Enter) it will begine to install; accept or press OK when asked.
Then, when finished the installation and while in LibreOffice, if you press F1
your internet browser will open to show the offline help (don’t require internet conection). Since the Help don’t cover all that could come to one’s mind, may be sometimes you will need to comeback to ask.libreoffice.
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