Ubuntu 13.04 does not come with Adobe Flash Player/Plugin installed by default. We need to install this software manually. But don't worry, installing Adobe flash plugin on Ubuntu 13.04 is very easy. We can do this via Ubuntu Software Center.
To install Adobe Flash Plugin, go to Ubuntu Software Center and type flash on the search box. You will see Adobe Flash Plugin listed as below.
Click it and press Install to start the installation. That's it. Its pretty simple right?