When you purchase the mini-amp, also get a couple of the 6’ patch cords that have the 1/8” stereo plugs on both ends (RS #42-2387) these are all that you need.
Cord #1 plugs into the earphone, or external speaker jack of your mp3, portable CD player, or the existing port on the speaker of your Johnny S and the other end is plugged into the (IN) port on the amp.
Cord #2 plugs into the (Out) port on the amp. It may be nessary to cut the other end off of this cord so that you can separate and strip the insulation off of these two inner wires so that you can splice them to your two speaker wires. You don’t need a lot here, simply twist the wires together (one inner cord wire with one speaker wire) (two total) and wrap them with some elect tape so there is no bare wire to touch on anything.
The amp requires a common 9volt batt and has it’s own volume control. You will have to experiment with different settings that will give you clarity without distortion.