Just started delving into the Looper. Have scanned several videos on Line 6 and Youtube about looping but none explain how to switch and overdub presets and/or snapshots. There are videos that have people doing it but none that explains how. I tried switching to a preset between an overdub and the looper just shuts off. I am however using the simple one switch mono. Can anyone explain how to overdub and record different presets/snapshots within the same loop session?