Updating a PC-BSD system is a very simple process. PC-BSD is updated in a similar matter to installing software using PBI. You can check if your system is up to date by running the Online update utility.
Open the Start Menu and browse to "Settings > System Administration > Online Update". It will prompt you for the super user's password before allowing you to alter the system. You will have the option of setting the system to check for updates at a specified time daily or weekly, default is not to check. However the system will always check for updates at startup and you can manually check here by clicking "Check now". After editing any settings here be sure to click the "Save" button to save your changes. You will then be able to select, fetch, and install any updates the application finds.
To manually download an update go to www.pcbsd.org and find the "Download system updates" section (under the downloads menu on top of the site). As of this writing you can obtain updates from the download page . Download the patch for your version, such as PC-BSD 1.11a to 1.2. Once the download has finished double-click on the PBI file to begin the installation. It works just like installing a PBI but simpler.
DO NOT cancel the update while a patch is running, restart the computer or otherwise disrupt or interrupt the update even if it appears to be stalled. An update can take some time to complete. You will be notified when the update has been completed and be asked to reboot for all changes to take effect.