Start by opening the URL given above and download and run the correct installer version for your Windows variant.
There may be a security prompt you have to accept.
Continue the installation process.
Agree to the license.
Leave the component choice as given, go on by clicking "Next".
Leave the default installation locations as is and click on "Install".
Along with OpenVPN, there is a TAP driver being installed. You will have to accept its installation.
Before you press "Finish", check the box in order to start OpenVPN GUI.
Now, open the HomeTunnel Website and sign in. You can also choose to have you remembered for the next login.
Click the "Admin" button to go to your local HomeTunnel box admin interface.
Login to your HomeTunnel box (default password is "hometunnel"). If you do not see the login screen, you may have tried to setup your PC while not being connected to your home network.
Download and "Save" both credential profile files.
Afterwards, "Open Folder" with the downloaded files, select them both and copy them via right-click->"Copy" or by using Ctrl-C
Open the OpenVPN configuration folder (usually "C:\Program Files\OpenVPN\config") and paste the files there. You can also drag-and-drop the files.
Since the target folder is restricted, you will have to provide administrator permissions in order to copy the files.
After the files are in the correct location, right-clicking on the OpenVPN GUI icon in the task bar will show the VPN profiles. Now, you can choose one and "Connect" it.
There will be a popup with a connection log which will close automatically when the connection succeeds.
A balloon will show up over the taskbar and the OpenVPN GUI icon will turn green once you are connected.
Always remember to disconnect your VPN connection after use, because it will continue to cause data traffic while active.
Now would also be a good time to change the password on your HomeTunnel box. Congratulations, you are good to go!