Below the summary of available updates, the update viewer gives and
    indication how long ago the last check (or “refresh”)
    for new updates happened, and when updates where last installed.
  
    You can choose to manually refresh and verify the presence of
    updates by clicking the Refresh button.
  There is a option to view the history of updates including
    previous installations, removal or updates of software.
  
    Use the Update System button to install
    all available updates or use the Review
    button to review and select individual updates.
    If you do not want to install updates at this time, you can just
    close the window.

su -
--- your root password when asked ---
yum update