Help page information about creating subform-mainform relation is out of date

Help page information about creating subform-mainform relation is out of date

https://www.zoho.com/creator/help/forms/creating-subforms.html#Creating_relationship_between_mainform_and_subform

The second bullet under this section does mention some actions which don't seem to be related to C5 but to C4.

  • Select the SubForm report from the Reports tab, click on "Column Properties" and select the lookup field created above and click on "Link " button, to create a link to the MainForm data.
I've did use the "Configure Fields for Web" window belonging to the related report and have added the lookup field into the report. I'm assuming that this is the proper way to achieve this subject.

I still have a problem when I add a row to the subform through the mainform. The row that I'm adding doesn't include the ID information belonging to the record from the mainform.

What could be the issue here?