In order to setup VPN on android devices:
1) open the Settings app and tap More under Wireless & networks. (On Android 2.3, tap Wireless & networks.)
2) Tap the VPN option on the Wireless & networks screen. (On Android 2.3, tap VPN Settings.)
3) Tap the + button and provide the VPN’s details. Enter a name to help you remember which VPN is which into the Name field, select the type of VPN server you’re connecting to, and enter the VPN server’s address (either an address like vpn.example.com or a numerical IP address).
4) Tap the VPN to connect once you have set it up. You can have multiple VPN servers configured and switch between them from the VPN screen.
5) You will need the username and password your VPN requires when you connect. However, you can save this account information for next time.
6) While connected to a VPN, you will see a persistent “VPN activated” notification in your notifications drawer. To disconnect, tap the notification and tap Disconnect.
The following Visual configuration guide could give you better idea of setup guide to ensure you are on a right path:
https://forums.androidcentral.com/e...com%2Fconfig%2Fandroid_pptp%2F&token=dKCRmcf8
Hope it could help