Click the DOWNLOAD button above, save cryptostorm_setup.exe somewhere, then run it.
Click "Run" if you get the security warning that "the publisher could not be verified". If you get a blue "Windows Protected your PC" window, click "More info", then click "Run anyway".
Choose "Yes" when prompted by User Account Control.
Follow the prompts in the installer.
Click "Finish" to complete the installation and start the client.
Copy your token from the welcome email, or if you received it in-browser, from there.
Paste your token into the main window, next to where it says "Token:", then click "Connect".
Select a server from the dropdown list on the config generator page, or select "All servers"
If you selected an individual server, save the .ovpn config somewhere then import it into OpenVPN by clicking the OpenVPN GUI system tray icon, then going to Import -> Import file.
If you selected all servers, save configs.zip somewhere and unzip it to C:\Users\%USERNAME%\OpenVPN\config\
Right click on the OpenVPN GUI system tray icon and select the server you want to connect to, in the sub-menu that appears click Connect
On the next page, click the server you want to connect to, then click the green DOWNLOAD button
Or if you want to download all the configs, click the "All configs" option, then the green DOWNLOAD button
Back in the WireGuard window, click Add Tunnel in the bottom left then navigate to the config you downloaded (or wg-configs.zip if you selected All configs)
Select a server from the Tunnels list, and either double-click it or click the "Activate" button to connect