This instruction for GNOME on Debian/Ubuntu

First, install packets:
$ sudo apt-get install openvpn network-manager-openvpn-gnome network-manager-openvpn

Next:
Open the GNOME settings

Go to the Network

Tap to “+”

Go to https://app.vpn.asia/support and generate a configuration file for OpenVPN

Select VPN and Import from file

Select the generated file

All configuration will be made.
You should enter your credentials and select the CA certificate file downloaded from https://app.vpn.asia/software/configs/ca-openvpn.pem

( if file not open, its in this zip also: https://app.vpn.asia/software/configs/files.zip )

Tap to “Apply” and now, you are able to connect!

If you want to connect through OpenVPN Stealth mode, you should install Stunnel packet:
$ sudo apt-get install stunnel

Next:
Download the configuration file https://app.vpn.asia/software/configs/stunnel.conf and put it to /etc/stunnel/stunnel.conf

( if file not open, its in this zip also: https://app.vpn.asia/software/configs/files.zip )

Then open this file in the editor (example, gedit)
$ sudo gedit /etc/stunnel/stunnel.conf
And add your server with port 443 to the “connect” directive.
Save the file

Then, enable stunnel and start the daemon
$ sudo sed -i 's/ENABLED=0/ENABLED=1/' /etc/default/stunnel4
$ sudo service stunnel4 start

Go to the VPN configuration and change the Gateway to 127.0.0.1

Tap to the “Advanced” button and change the port to 1194 and the protocol to tcp.

Done.
Now you are able to connect through Stealth mode.