Step 5: In goes the Output
The speaker has two wires coming to it from the PCB. One goes to the positive terminal, one goes to the negative terminal. These should be marked on the speaker itself, but if not, dont worry, it's pretty easy to fix if you wire it backwards.
Take your output jack of choice (I used a 1/4" mono guitar jack, but you can use 1/8" jacks, RCA plugs, etc.) and wire one lug to each of the lugs on the speaker. I recommend trying out the various possibilities for wire placement with some alligator clips first, as those are easier to reverse than soldered wires. When you find the configuration that works, solder in the wires.