If you are looking for to create shortcut for app that you prefer to use from TAR source, following procedure will help you.
Create new shortcut using existing .desktop file.
sudo cat /usr/share/applications/mozilla-firefox.desktop > /usr/local/share/applications/ffd.desktop
Edit newly created .desktop & change path for executable & images.
sudo gedit /usr/local/share/applications/ffd.desktop
e.g
Exec=/home/dhaval/myappz/nightly/firefox %u
Icon=/home/dhaval/myappz/nightly/icons/mozicon128.png
