This is basic of what I found,
Install Putty on laptop
Put FQDN of Vcenter appliance, Login as Root
Type shell hit enter
Type in /usr/lib/vmware-vmca/bin/certificate-manager
Choose choice 1, then No, then login with SSO ID administrator and password1
Choose choice 1: Generate Certificate Signing request and key for Machine SLL Certificate.
Then provide a path to a location to can send and retrieve from.