In this section you will specify which field of the tag form should be linked to the field of the templates.
Here you will find the XML template fields that contained an ID.
And on the right you have the formulas to choose the fields you want from the system calculator.
Smart link: At the top right you will see a magic wand. When you click on it, it will search for all the fields that have similar names and will try to link the best options.