Important: First: Backup! having a recent backup can (and probably will) save you a giant headache at some point when you do run into a site breaking error.
Download the latest version from CodeCanyon.
Extract the main package.
Read special instructions for update in package (if any)
Copy website.zip file to the root of your server (same place where files were uploaded during installation).
Extract the website.zip file into the root directory and overwrite old files.
Some versions require special instructions that are included in the package in text file, make sure you read the instructions before you proceed with the update.
After upload login to your admin panel and Visit http://yoursite.com/admin/update URL(replace yoursite.com with your website URL) and click Update Now button. Once update is completed you will be redirected back to dashboard.
Note:
If your server or hosting provider uses some kind of file caching (supercacher, opcache, cloudflare cache etc) you will need to clear that cache after updating, otherwise some changes from the update might not work properly.