Assuming that you have a openVPN server ready to allow vpn connectivity from its clients. It is also assumed that CA Certificate (.pem) is also obtained from a valid CA and signed with the openVPN server.
Because the large number of parameters you can define either in the configuration file or in the command line, you could configure OpenVPN in many different manners. In any case, to obtain a connection with a opnVPN server, you only need to define a small number of them in your client's configuration file. In order to further simplify the configuration of the OpenVPN client, you could use an example of configuration as below: