@tadpole
A quick and simple way to tell if speakers are working is the battery test. Get one AA 1.5 volt battery, a length of speaker wire, and some tape (any tape will do, scotch or masking).
Speaker wire consists of two conductors bundled together, sometimes call zip cord. It's no different than standard lamp cord you can find in any hardware store. There is always a way to tell one wire from the other. There can be different colors on the plastic insulation, or ridges that you can feel on the surface. I've seen some zip cord with a cotton thread inside the insulation of one of the wires, or one of the wires is copper colored while the other is tinned, so it looks silvery.
Attach one of the speaker wires to the red terminal on the back of one of one of your speakers. Similarly, attach the other wire to the speaker's black terminal. Tape the bare end of the wire coming from the speaker's black terminal to the battery's Negative – terminal.
Sit so you can easily see the cones of the speaker. Touch the wire from the speaker's red terminal to the battery's Plus + terminal. You'll hear a pop sound. At the same time, you'll see the speaker cones pop forward. The cones will return to their normal positions when you remove that wire from the battery's Plus + terminal. It's OK to do this several times just to be sure all the cones are working.
If you have things wired in reverse, it won't cause any harm. Instead of popping forward, the cones with pop inwards.
Don't worry, there's not enough juice in the battery to shock you.
This battery test will only tell you if the speakers can work, but it won't tell how good they'll sound.