How to open applications?

How to open apps in Ubuntu 12.04 to read documents, play music and video, surf the net and reading emails?

As per @devav2:

_{Use dash. To open dash press 'Super key/Windows key'. For Documents - Libreoffice, Evince. For Music - Rhythmbox . For video- Totem . Surf the net - Chrome/Firefox. For Email- Thunderbird/Evolution . These apps come by default on Ubuntu. Other than this there good apps which can be found on Ubuntu Software Center}

Libreoffice is like Microsoft Office and supports most of its formats.

To listen to music, you can use Rhythmbox. Video can be played with Totem.

TO surf the web, you can use Firefox, or Chromium if you install it in the Ubuntu Software Center.

To read email on your computer, use Thunderbird or Evince. You can open any of these by clicking the top left button in the launcher(dock-like thing at the left with all the buttons) and typing the name of a program. You can install many more useful things with the Ubuntu Software Center. Many applications there are free, and can be installed as easily as clicking the Install button and giving your password.