OpenVPN is no longer supported since February 2023.
Run the openvpn app (you can do a search in the search bar for 'openvpn').
Go to the tray. It's at the bottom right corner of your screen; there should be lots of small icons there.
Right click on the OpenVPN icon (if you can't see it, click on the small up arrow to reveal more icons).
Select a server, and click "Connect".
A pop up will appear. It will ask you for your username and password from step 3. Paste them in.
Wait for it to connect and enjoy the internet.
To disconnect, right click on the icon, select the server you're connected to, and click "disconnect".