I am following those steps. When I get to this:
"Use the [+] button to select field values from your data. The field values contain field aliases followed by the field names. By default, the primary field is displayed."
No fields are present and there is nothing for me to select. If I click on a feature, I see all the fields included in the pop-up. I'm not able to configure this.
After further investigation, this seems to be happening only on feature classes that have that related table information. So... is it the case that pop-ups cannot be configured if there's related tables??
Thanks.