Plugin should notify you about new versions automatically, and update itself if you enter your Purchase Code from CodeCanyon to the plugin’s settings page.
Manual upgrade procedure
If you download new plugin version from CodeCanyon please follow these steps to upgrade from the existing version:
1. Go to your FTP and open WordPress plugins folder
2. Delete the old wpDataTables version folder
3. Upload the new version of wpDataTables
4. Go to WP-admin panel, open Plugins section.
5. Deactivate wpDataTables, and then activate it again.