Login on your DD-WRT router panel and then click on Setup tab > Basic Setup.
Select L2TP for Connection Type then enter the following settings:
Gateway (L2TP Server): se-sto.pvdata.host
*you'll find the server list here.
Username: (your PrivateVPN registered email)
Password: (your PrivateVPN password)
Use DHCP: Yes
MPPE Encryption: No
Require CHAP: No
Refuse PAP: Yes
Require Authentication: Yes
Dual Access Mode: No
Receive IPTV: No
Click Save button below and then click Apply Settings.
You may verify the connection status by going to Status tab > WAN.