Once installed, Skype Call Recorder should appear in your desktop environment’s menu in the category Utilities (or Accessories). If it doesn’t appear in the menu, you might have to reboot your computer. If it still fails, then you will have to manually add it, or launch it by invoking ‘skype-call-recorder’.
After launching it, you will see an icon in the system tray. This icon is gray while the connection to Skype is not established; upon connecting to Skype it will be colored. Click it to perform actions like opening the preferences dialog, or start/stop calls. Note that Gnome 3 sometimes doesn’t have a system tray by default, you can press Win+M to make it appear. (Win is the key with the Windows logo)
Important: In some countries, it is illegal to record Skype calls if you don’t have the explicit permission of all participants! Be sure to ask for permission to record first. For more information, google for call recording legal.