You may not have been able to see the qRules data source because the data source task pane by default displays in a simple mode in a SharePoint List Form. There should be a link to show the "advanced" (i.e. normal) data source task pane.
However, SharePoint List forms, except those for external lists, cannot have code. So, unless your list is an external list, qRules will not work in your form. Also, so you know, we have not tested qRules in SharePoint External List Forms.