Before you go ahead with the update please check template changelog on product page. It is the best practice to backup both your files and database regularly and especially before making some serious updates. We recommend using free backup component for Joomla! like Akeeba Backup. Typical template update process is easy. You can manually reinstall new template using a new package. Second option can be done from Extensions: Update but request from you filling two fields License Key and email in template "Update settings" tab.