For each music entry, start the line with Lump, followed by a space, followed by the music file's lump name (i.e. the part of the filename that comes after the D_ or O_ part, and not including the .mid or .ogg part). Now make a new line and field named Title = , and follow this with the display name you want this song to show as in the Sound Test menu. Make sure each word/etc. is separated with an underscore, not a space. The maximum character limit that the title ribbon in the Sound Test will display is 31 characters, but instead, try to keep the Title string no longer than 16 or 17 characters; the musical note icon that appears at the other end of the blue menu box may partially obscure the 17th character, and any characters beyond 17 will simply trail off of the menu. For the next line, you can optionally create a field named Alttitle = . This is where you can put in an alternate name for the song, which will show up in the title ribbon alongside the original Title field. Otherwise, the next field should be Authors = . This is where you will put the name(s) of the Composer(s) of the song in question, separating each artist's name with a comma (although this is technically not necessary; it's just nice for formatting). However, if you don't know this information, you can just remove this field entirely. For the next line, just leave Soundtestpage = as 1. For the line after: Soundtestcond = can just be 0 if you have no intention of making this song be an unlockable; otherwise, this number corresponds to the extended map number of the map which should be completed to unlock this song, or -- if the number is negative, a condition set. Refer to the MUSICDEF page for more information on this and other fields.
The last field is BPM = , or Beats per Minute. This is where you put in the tempo of the song; the bouncing radio/boombox graphic to the left of the Sound Test menu bounces up and down in relation to the value of this field. e.g. Greenflower Zone Act 1's music plays at a BPM of 132. If you're not sure how to find the BPM of your music, just experiment with tweaking this value until it seems fast or slow enough for your liking; it doesn't have to be exact. Ultimately this is another field that is also just for show; putting in 0 means it will not move at all.
The last example we have shows more advanced use. A common request is for example wanting to list every file on the SD card, or play ever music file or similar. In the latest version of the SD library, you can recurse through a directory and call openNextFile() to get the next available file. These aren't in alphabetical order, they're in order of creation so just watch out for that! 2b1af7f3a8