This video explains it. It's all over the place, so start watching where I've got it queued up at 3:30. He shows the four terminals to de-solder to remove the original speaker and which two terminals to solder in the programmable speaker. The other two terminals just hold the old speaker to the board. The speaker can be mounted like any USB flash drive and you can transfer whatever MP3 you have to it.
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Although this speaker can play more accurately, I'll probably load it with something from the 8-bit library.
Might be Immigrant Song first
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Or, get my Star Wars on with the Cantina Theme
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