OpenVPN Installation step by step

sudo apt install openvpn easy-rsa
cd /etc/openvpn
sudo chmod 400 /etc/openvpn

Paste crt , conf and other file in /etc/openvpn

cd /usr/bin/
sudo nano vpn.sh
sudo /usr/bin/vpn.sh
sudo nano /usr/bin/vpn.sh

!/bin/bash

cd /etc/openvpn
nohup openvpn --config sumant.conf &
sudo chmod +x /usr/bin/vpn.sh
sudo /usr/bin/vpn.sh

you can also use best GUI tool Pritunl