Opera is a small ,fast,customizable,powerful and user-friendly web browser,as well as a internet suite,including a email client,and IRC client,and web developer tools.Below steps will show you how to install Opera in Ubuntu 12.04.You can refer here to see more features of Opera,here we go.
1.Download Opera .deb file from official site
2.Right click the Opera .deb file and click Open with ubuntu software center
3.Then click Install ,input your password if prompted
4.You are done,now you can launch Opera from Dash.(You can drag it to launcher use mouse)
5.You are done,enjoy.
6.(Optional)For uninstallation, just launch Ubuntu Software Center,go to tab Installed , then you can find Opera under Internet,then click Remove to uninstall