Now open Settings - Network and click the + button next to the VPN then select IPsec/IKEv2
Now input your specific VPN settings from the https://realvpn.io/settings in the opened dialog as shown in the image below.
Use the switch to enable VPN connection.
In case you have issues with the default gateway on your Linux, use the following instructions.
Edit /etc/netplan/50-cloud-init.yaml (or other yaml file you find in /etc/netplan/)
renderer: NetworkManager # add this line
And then run sudo netplan apply
Well, you will need to edit some files, and you will be ready to go.
sudo nano /etc/NetworkManager/NetworkManager.conf
Change managed=false to managed=true
sudo nano /usr/lib/NetworkManager/conf.d/10-globally-managed-devices.conf
Add except:type:ethernet to this line: unmanaged-devices=*,except:type:wifi,except:type:wwan
Restart network manager:sudo service network-manager restart