Don't use that offboard wiring for this. That's for pedals, this is an amplifier. You don't need a stomp switch at all.
Just wire it exactly as it's labeled on the layout: Wire the input jack tip to the spot marked 'in jack tip', etc. The 'Speaker +' and 'Speaker -' points should be connected to the +/- lugs on the speaker itself (for a combo) or to the output jack* (for a head). You can put an SPST inline with the power supply if you want to be able to turn it off without unplugging the adapter.
*Note that the speaker should not be connected to ground, so if you're using a metal enclosure to make a head, you'll want to use isolated jacks for the speaker outs.