VPN configuration in Windows
All the modern versions of Windows feature almost the identical way to configure VPN connection. This instruction will be suitable for Windows 10, 8 and 7, and there’s no reason to discuss older versions.
1. Press Win and R buttons simultaneously (details about Win button), type "control.exe" in the appeared window and press Enter button.
2. Control panel will appear. In the searching box (in the top right part of the window) type “Network” and move to “Set up a virtual private network (VPN) connection” section:

3. Type in the IP address of your VPN sever and the connection name (any one you like), then click "Create" button:

4. Your VPN connection is ready. To connect to the server, click the network icon next to the clock in the bottom right part, select your VPN connection and press “Connect” button in an opened window. When being connected for the first time, you will need to type in login and password.
VPN configuration in Android (smartphones and tablets)
The Android operating system supports VPN connections by default, you don’t need to make any additional configurations.
1. Proceed to Settings -> Connections -> Other -> VPN (the names of the sections may slightly vary in different Android versions).
2. Create a new VPN connection, type in the name and IP address of your server:

And click "Save" button.
3. That’s all! To connect to the server, select the VPN connection you need and just connect. When being connected for the first time, you will need to type in login and password.
Configuring a VPN connection for iPhone and iPad
1. Move to Settings -> General -> VPN and click "Add VPN configuration".
2. Select "PPTP", type in a description (any), IP address of the server, login and password. You won’t need to amend other sections:

3. Click "Save" button, and then just move the changer and VPN connection will be set up.
If you have any questions left or needs some details – please, ask a question or leave a comment.