You can find a similar documentation to install and configure almost everywhere.

apt-get install openvpn easy-rsa

Create your configuration

gunzip -c /usr/share/doc/openvpn/examples/sample-config-files/server.conf.gz > /etc/openvpn/server.conf

Edit the following in “/etc/openvpn/server.conf

#from
dh dh1024.pem
#to
dh dh2048.pem

in work