Make apps stop showing as mounted partitions I am new to OS X and have been using it for 5 days.

Whenever I launch an application, it shows up as a mounted drive in finder and on the desktop. This looks useless and annoying. Is there a way to prevent apps from showing up as mounted drives?
If you download an app, it comes packed as disc image in most cases (a file with .dmg extension). If you open this file, this drive image is mounted as new drive. You should move the application that is on that newly mounted drive to your application folder. The image file can be unmounted and deleted. Be sure not to copy the dmg file to your application directory (you can check file extensions by selecting the file and press command+i).