Need to replace server/client keys and all

[mn918_79Sh]

Sorry but I'm not very experienced with Linux. Small HPE business server with static IP in next room . I can access it directly 24/7 either with HPE iLO4 logged into the static IP wireless router or right at the server. About 5 months ago I bought the server and installed Ubuntu Server 16.04 (0 Linux or server experience), antivirus, did security patches and some other utility applications then had an outside admin set up OpenVPN and Samba Server. It works fine and is used for file transfers between 2 other employees and myself in different states. I will be the third client for OpenVPN even though I don't need it. The freelance admin who set it up remotely ssh'ed in to do his work and I have since fire-walled the port and disabled ssh for security reasons and now I need to generate and install all new certs for the server and 3 clients for security. I have located all the folders containing the relevant files and I've been reading about this for at least a month off and on and I still don't know if I can just generate the specific certs and keys I need for the server in a different folder then rename the files to the ones in use and move them or if I have to start with clean-all and rebuild everything from scratch. I'm going to work on this Monday and either way I'm game. The previous admin generated the certs on a windows computer the first time but the second time via Teamviewer used easy-rsa on the server to generate the files and get the server up after I upgraded to 18.04 and the server got buggy.
Thank you in advance for any help.