To create new ssl for a domain,
login to whm, then goto ssl/tls -> generate ssl certificate and signing request. For wildcard domains, use *.xxx.xxx. You should get a private key and a sign request. Then go to the ssl provider and give them the signing request. They should give you a CA cert.
now go to ssl/tls -> install an ssl cert on a domain, browser the cert and paste in the key. If there are api or permission errors, go to /home/user/ssl and chown user:user -R *.
now go to https://www.yoursite.xx or https://yoursite.xx and it should work.
to install ssl for the whole cpanel or whm or other services, login to whm -> service configuration -> service manager -> manage service ssl certificates. browse a cert and install.