You question is a little unclear. Are you asking how to find the application on your computer or where to find the application online to install?
If you need to install just do this for the easiest way:
sudo apt-get install supercollider
If you need to find it in ubuntu, just open the dash and start typing supercollider and it should come up with a circle icon. Not sure those are the answers you were looking but maybe that answers it. Best,
Chad