This query looks for the fieldId "fullName" from the connected List in a Tagbox (persons) that is on the Layer Corporate Information. You must use this syntax to get a specific value from the tag assigned: layer.tagbox.listfieldid:value
You can access values from nested documents following the same approach. Assuming a Tagbox "Persons" links to a Tagbox "Department" which links to "Office" which links to "Location" which has a Text field "Name".
Therefore you must ensure that all those levels are available in the search.