In cPanel, go to the “SSL/TLS” section. Click on “Manage SSL Sites” or “Install an SSL Certificate on a Domain.” Paste the contents of the .crt file you received from the CA into the “Certificate (CRT)” field. Paste the contents of your .key file (the private key generated with the CSR) into the “Private Key (KEY)” field. Paste the contents of the ca-bundle or CABUNDLE file into the “Certificate Authority Bundle (CABUNDLE)” field. Click “Install Certificate.” cPanel will verify the entries and apply the SSL to the specified domain. Once installed, your site will run over HTTPS.