I added some maker stickers to the outside case of the speakers. Since we'll be able to see inside the case, I thought it'd be nice if there was some cool graphics. I used Sparky the blue monster and an OSH Park sticker, but also a Raspberry Pi and OctoPrint octopus looks pretty cool.
The left and right sides of the case features holes for the speakers. On the side of the case are two tabs. These tabs actually hold the speakers in place without having to use any glue or screws. Orient the speaker so the openings line up with the speaker cone. Then, insert the speaker so it slides in between the tabs. Firmly press them in so the tabs click into place.
Repeat the speaker installation process for the second speaker. Try to keep the wires from being kinked when pressing them into the tabs. You may need to press firmly to get the right speaker in because there's a feature on the side of the case (it's for holding the switch).