Hi Daveyboy,
Give this a try this
In a browser, copy & past this link
file:///usr/share/doc/litemanual/index.html
If it works, create a browser bookmark and call it Help Manual,
This can be done in any browser.
If the above doesn't work or you just want another link, here's one to the online Help Manual
http://www.linuxliteos.com/manual/
Same information, just a different location.
As for the help icon error, here's what should be in the command field in the launcher properties
xdg-open /usr/share/doc/litemanual/index.html
To edit the icon launcher properties
Open the main menu utility with Menu > All > Main Menu
Main menu window opens
Click/Choose Xfce on left
Click/Choose Help Manual in middle
Click properties on right
Launcher properties window opens
Compare the information in the Command field with that listed above.