I’ve downloaded the help pack to install in LibreOffice portable on my usb stick, so I can get help offline. However, I can’t get it to install. What am I doing Wrong?
You need to unpack the .msi file using an explicit command giving the target location.
See
and there the link
this rather exhaustive guide
which gives a detailed instruction.
(There is also this pdf version of the guide.)
Please note that recent versions of LibO will display the offline help in a standard browser on the system, which must be avaiable therefore.