Joseph,

 One way to do this is to open the "_Layout.cshtml" file which is found in the "Shared" folder located at  "\Program Files\Laserfiche\Laserfiche Forms\Forms\Views\". Right before the "</body>" element you will want to copy, paste, and save the following code:

<script type="text/javascript">
$(document).ready(
  function(){
    var help_url = "https://mycustomurl";
    $("#topnav-help").attr("href",help_url);
  }
);
</script>

Just change the variable "help_url" to your custom url and you should be good to go.

Hope this helps!