For the safest and most universal solution, Usemyvpn prides itself in using the official OpenVPN Connect applicaton available in the Apple App Store..
Visit the VPN Profiles page by clicking here or simply clicking on the VPN Profiles button on the Getting Started page.
On the VPN Profiles page, please click on the city you would like to connect to.
Once you choose the city you'd like to connect to, click on "Open in OpenVPN".
In the OpenVPN application, click on the "+" symbol below the profile you've just imported.
Next you can enter your VPN login credentials, click on the save button, and click the slider below the disconnected status in order to connect.