To use the SHACKTRAX SHACKBOX you need the "Sibelius Scorch" plugin installed on your computer. It is totally free, safe, and you need to download it only once per computer. (To use it in more than one browser, download it once for each browser, from that browser.)
To download the plugin, click on the link below and follow the instructions on the "Sibelius Scorch" download page.
After it's downloaded, simply click any selection on SHACKTRAX SHACKBOX, wait for the scorepage to appear, and click the "Play" button on the control-bar above the score to start playback. (Pass your cursor over the control-bar to find out what the other buttons do.)
You can also simply type p to play and o to stop, or just click anywhere on the score to begin play from there. The moving blue line follows the notes as they are played.
For the best sound, use good stereo headphones; a top-quality sound-card in your computer will produce top-quality stereo playback.