WiseMysticalMammoth 2: Electric Boogaloo

how the hell do i use this thing

here's an example:
function filter(number) {
for(var i=0; i<songNumberList.length; i++){
if(positionList[i] < number){
appendItem(filteredArtistList, artistList[i]);
appendItem(filteredTrackList, trackList[i]);
appendItem(filteredPopularityList, popularityList[i]);
appendItem(filteredPositionList, positionList[i]);
}
}
}