The standard steps for installing a custom security certificate or SSL are to get the CSR generated [which is unnecessary for most SSL renewals, just the first installation], provide that to the certificate authority, and then get the CSR and possibly some other bundled files in return.
Once you have that bundle you can upload the files through your SSL tools in cPanel.
SSLs REQUIRE a Dedicated IP address assigned to your cPanel in order for the last stages -- Activation -- of your SSL to work. Additionally, you can only have one SSL per cPanel account.
The Generate portion is at the base of the Private Keys screen.
Upload the files to the "Certificates (CRT)" section [you may need to UNZIP them first].
The information should automatically populate for the CRT in the upper box.
Open the bundle or ca/chain file in Notepad and copy the contents into the CA Bundle box.
If you run into any trouble getting things in place it may be easiest to assist you via phone or chat, so feel free to contact us!