After you purchase and install an add-on interpretation engine, you can choose settings for it on the Advanced tab of the Field dialog. (The settings are disabled until you install the new engine.) Follow the advice in the instructions supplied with the engine.
Apply the engine to a specific field definition by choosing that engine, or FORMS + that engine, in the drop-down list on the Advanced tab of the Field dialog.
External setup is activated when an external engine allows you to set parameters that cannot be set via the DLL interface supplied with the engine.
Choose whether you want to use the second engine on demand or whether it should be called each time the field is interpreted.
Choose which kind of voting is to be used when the external engine is called.