This example was done on Samsung S9 with OS Android 8

• On the Apps page tap Settings

• Tap Connections

• Tap More Connection Settings

• Tap VPN

• Tap the + to add a connection

• Name is whatever you want to name this connection.
• Be sure to choose PPTP for Type
• Server Address is the IP or hostname of your PPTP server.

• The first time you connect you will be challenged for credentials
• In Username enter the Username given to you by your administrator
• In Password enter the password given to you by your administrator
• If you do not want to be challenged in the future tick Save account information

• Tap Save

It is important that you disconnect as soon as you are done using the VPN. All Internet traffic will go through the VPN until you disconnect.

• Tap the connection you are using
• Tap Disconnect

• On the Apps page tap Settings
• Under Connections Tap More connection settings → VPN
• Tap the VPN you created. Enter credentials and check Save account information to save password tap Connect

It is important that you disconnect as soon as you are done using the VPN. All Internet traffic will go through the VPN until you disconnect.

• On the Home Screen swipe down from the top
• Tap VPN Activated
• Tap Disconnect

You can also got to Settings → Wireless and Networks… → More → VPN Tap the connected VPN then tap Disconnect