Start the Settings app.
In the Wireless & Networks category, open More... and select VPN.
Click the Add VPN profile button.
Input Name field (e.g. BoxPN). Choose L2TP/IPSec PSK type and specify Server address. Use pre-shared key: s3CuREpaSs412
Now you can start a VPN connection.
Open the VPN connection.
At the first time of using, you have to input username and password.
Enter username and password, save account information.
Connect to start the VPN connection.
Сonnection is established.