Proceed to Synology Control Panel.
Click on Network.
Select Network Interface at the top tabs then choose Create VPN Profile.
Select L2TP/IPSec and then click Next.
Enter the following settings:
Profile name: (any name would do)
Server address: se-sto.pvdata.host
*you'll find the server list here.
Username: (your PrivateVPN registered email)
Password: (your password)
Pre-shared key: privatvpn
*without the 'e'.
Click Next.
Authentication: MS CHAP v2
Enable Use default gateway on remote network and Reconnect when the VPN connection is lost.
Click Apply.
Select the VPN profile that you have created and then click Connect.