How to Map an Apogee GiO Stompbox button to a MainStage 3 Stompbox effect
In the MainStage 3 Patch List window, click on a patch to edit.
Click on the Assignments & Mappings tab.
Click on the desired Smart Button (Smart Button 1, Smart Button 2, Smart Button 3, Smart Button 4, or Smart Button 5). RESULT: The row turns blue.
Click on the Assign & Map button, located on the top right hand corner of the Assignments & Mappings window. RESULT: The row turns red.
Click the desired Apogee GiO Stompbox button 3 times, slowly and deliberately. IMPORTANT: A light on the left side of the row should appear then disappear. Wait for the light to disappear.
In MainStage 3 open the Pedalboard, by clicking the Pedalboard button in the associated channel strip.
Click in the On/Off button on the MainStage 3 stompbox effect you want to associate with the Apogee GiO stompbox. IMPORTANT: Click the On/Off button to cycle through the On/Off sequence. RESULT: The row highlighted in red will indicate that the Pedal State has changed. "Pedals > Pedal State".
Turn off the mapping functionality by clicking the Assign & Map button. RESULT: The row turns blue.
Click on the Workspace tab and close the Pedalboard window, if desired, to continue working on your patch.
END RESULT: The newly mapped Apogee GiO Stompbox button (for example, GiO button 1 [left-most]) should toggle the on/off state of the MainStage 3 stompbox effect, (for example, MainStage 3 stompbox effect 1[left-most]).