in the GUI~Editor, in the lower left, click on 'Filter', and then click on the popup of 'Show Library Elements', so it is checked in, this reveals all of the built-in quest stuff as light greyed font~text (on the left side, the 'tree of stuff'), and see if you can find 'help', and then decipher (try to understand if you can) the coding of it.
otherwise, you can simply create your own 'help' COMMAND too:
<command name="help_command">
<pattern>help</pattern>
// or: <pattern>help #text#</pattern>
<script>
msg ("Type in: blah, to read about blah)
msg ("Type in: blah, to read about blah)
msg ("Type in: blah, to read about blah)
// and many other code designs for doing various things, such as maybe a 'pedia' system
// switch (text) {
// case (blah) {
// }
// }
</script>
</command>