To get usable music, simondotm's vgm2electron script is required, which can convert VGMs of BBC Micro tunes to Acorn Electron compatible data.
Electro-Player can then be modified to take the data by replacing this line in player.asm with the output .bin file of whatever music you have converted.
incbin "caramelldansen.bin"
Then the player is to be assembled with BeebAsm using the included build.bat file.
This should produce an .SSD disk which can then be loaded on either an emulator or a real Acorn Electron.