You need two things :

.ovpn the file that is attached to the opening address of your VPN sent YOORShop. We will take as example here mondomaine.ovpn (yours will of course another name in connection with your customer ID YOORShop)

Tunnelblick free software that will give access to OpenVPN

Proceed in this order :

mondomaine.ovpn import the file to the desktop of your computer. Do not open it.

install Tunnelblick. You will find installers to download here: https://tunnelblick.net/downloads

If you are on MacOS Sierra you must choose Tunnelblick 3.6.9beta01.
If you are on an older system version you can choose the stable version 3.6.8

Once downloaded the installer do the usual: double-click the installer and let it guide you! The installer will ask you:

If you want to make updates automatically or manually. Choose instead automatically. Attention however MacOS Sierra beta version does not update automatically. It will do so manually. View Google https://groups.google.com/forum/#!topic/tunnelblick-discuss/lzAqJY7qHgg forum

If you want to share tunnelblick or reserve it for personal use: You choose !

When tunnelblick installed, bouble-click the mondomaine.ovpn file that is on your desktop. It installs and configures itself tunnelblick with your settings.

An icon appeared in the top menu bar of your screen. This is your gateway to TunnelBlick

Open Tunnelblick

Proceed by choosing 'Detail VPN' appeared in the new menu

On the panel that opens you have 5 choices on the top bar. Choose 'Settings'.

You see that in the left frame containing configurations contain the name of your mondomaine.ovpn file. Ie mydomain.

Select the 'Settings' tab. The only thing to adjust is the connection mode you want. In the dropdown menu 'Connect' you have 3 choices: 'manually' - 'At start Tunnelblick' - 'When the computer starts'. Choose.

Do not touch the rest

Click on 'Connect' lower right. A small panel appears at the top right of your screen that allows you to follow the steps of the connection.

Now select 'Preferences' on the top of the panel. In the 'Updates' check that the three options are checked (if the check) even if for the moment the automation does not work very well on the beta. It's click 'Find Now' you will know if you have the latest version of Tunnelblick.

Installation is complete

You can explore other choices of the panel. 'Appearance' for example allows you to customize some details "cosmetic" if you wish.

ATTENTION :

If you are on MacOS version earlier than Sierra and if you ever decide to move to Sierra, install 3.6.9beta version of Tunnelblick before the system update.

See the warning Tunnelblick : https://tunnelblick.net/index

These warnings certainly disappear when stable 3.6.9 version is released. To check !