How to get a clean patch:
To start, power up the amp and set the stompboxes and effects controls to “bypass”. Select one of the amp models (I recommend "Classic" or "Twn") with the amp control. Pressing the amp control will toggle between red (distorted amp model) and green (clean amp model).
Having done this, you will still notice reverb and delay in the sound. This is because the reverb and delay are GLOBAL effects, meaning they affect all models.
To turn off the global reverb and delay, enter edit mode by pressing either the stompboxes or effects control once. You should see the led next to “edit mode” light up. You can now turn the reverb and delay off, by turning the controls labeled “feedback”, “level”, and “level” to zero.
Now, exit the edit mode by pressing the stompboxes or effects encoder again. The edit mode led should go out.
At this point, you have a “dry” no effects patch with the amp model of your choice. If you want this patch to be your “default” patch, which comes up every time you power up the amp, you need to save it to bank A, preset 1. Do this by pressing and holding the preset 1 button until the red led next to it blinks once and comes back on.