There are two easy ways to share any Kompoz track on to the Community page.  

1. From the track detail page

Go to the collaboration files list, and navigate the the track you want to share.  You'll see the green Kompoz icon in a button under the track audio player.  Click that button to bring up the sharing dialog.  Add a comment and submit.  It will be added to the community page.

2. From the community page.

Go to the community page and type in a comment in What's on your mind? text box.  Before submitting, click the track button under the text box, and paste in the URL of the track you want to attach.  

Using either of the options will add the audio player to the community page.