Login to your client area (https://wannaflix.com/clientarea.php)
Click on your active SmartDNS subscription
Select your prefered Netflix region and click "Update"
Log in to the router. Common user names are: admin, root, default and common passwords are admin,1234, default, password (you can usually find the username and password on the router)
Find network settings and change the DNS to 126.96.36.199 and 188.8.131.52 (if there is only 1 slot, just enter the first one)
Apply the changes by saving settings.
Restart devices connected to the router.