ScoreHero is a Guitar Hero modding community that makes custom songs just like our community. The only difference is the way they package their custom songs. Frets On Fire needs a few extra files than are usually provided with ScoreHero community-made songs. Scorehero charts will usually only come with the notes.mid or a *.chart file. If one comes with any extra files, chances are they won't be needed for FoF.
Here's how converting charts from Scorehero works:
1. Get the .chart and .mp3 files
2. Convert the .chart to .mid
3. Convert the .mp3 to .ogg and add silence to the beginning if needed
4. Create song.ini and adjust delay
To convert the .chart file gotten from Scorehero to .mid file for FoF, it's recommended to use chart2mid2chart converter. You can download chart2mid2chart from here.
To convert the .mp3 to .ogg, use Audacity. Simply open the .mp3 in Audacity and export as .ogg (File -> Export as Ogg vorbis).
When you download a chart from Scorehero, remember to check the lenght and offset. Offset is the opposite of delay* (in song.ini) in FoF, so if the offset is 500, you need to add line "delay = -500" to song.ini. If the lenght differs from the lenght of your .mp3 (with bad luck even if it's the same), you may have to adjust the delay more depending on how it syncs. To create the song.ini, you may use the Song.ini Generator.
If the offset of the chart is 2000ms, it's very likely that the charter added 2 seconds of silence in the beginning of the song before charting. In this case, it is recommended that instead of adjusting delay in song.ini, you add 2 seconds of silence to the beginning of the .ogg in Audacity (Generate -> Silence -> 2).
Finally, put notes.mid, guitar.ogg and song.ini (remember to rename the converted files properly) in the same folder. The chart should now work in FoF.
When posting the conversion, remember to give credit to the person who made the chart.
*Delay moves the notes forwards, offset moves the song forwards.