https://knowledge.rapidssl.com/support/ssl-certificate-support/index?id=SO6252

SSL Checker: https://knowledge.rapidssl.com/support/ssl-certificate-support/index?page=content&id=SO9556

vim /etc/httpd/conf.d/ssl.conf

SSLCertificateFile /etc/pki/tls/certs/server.crt

SSLCertificateKeyFile /etc/pki/tls/private/server.key

SSLCertificateChainFile /etc/pki/tls/certs/server-chain.crt

Edit and paste the contents of the intermediate certificate:

vim /etc/pki/tls/certs/server-chain.crt

Edit and paste the contents of the private key:

vim /etc/pki/tls/private/server.key

Edit and paste the contents of the new SSL cert:

vim /etc/pki/tls/certs/server.crt

Restart the web server process:

service httpd restart

Now use the checker link above to test.