Help section is still under development. See you found the 'site help' command, which says type site ioahelp for help on the commands available with ioA. If you check your ioFTPD.ini you see this:
[Scripts]
## SITE <script> <parameters>
#
# !file = Show file
# @string = Alias
# %file = Execute file (translate cookies)
# file = Execute file
#
help = !..\help\help.msg
This means that help\help.msg will be shown when using site help command. I've done this file on request by Dark0n3 some time ago. I included the ioahelp.msg file as well. It is located in help dir bur not referred to in ioFTPD.ini. If you want it to be shown when using site ioahelp add this to the [Scripts] array:
ioahelp = !..\help\ioahelp.msg
But keep in mind that these files are not very up to date and that the whole help section in ioFTPD is not finished. If you want help for ioA just read your ioA.manual.txt. And (almost) all the help you need for ioFTPD here: http://www.ioftpd.com/board/showthread.php?s=&threadid=268