Press an Icon to play a Sound based on the outline color. Red = Music, either Items, Bosses, Maps or Emotes. Blue = Sound Effects for Items. Press on the Arrows at the bottom-middle part of the screen to switch between pages. Extended is an understatement, there are like 5 pages of sounds. I recommend going into fullscreen to see the icons better.
Wootson21 for the original version of the Item Asylum Soundboard.