When you have the certificate files available, upload them to the corresponding domain.
To secure your domain using a manual certificate:
Go to Setup > > Domains.
Click Edit next to the domain to which you want to add the certificate.
In the Certificate section of the domain form, click Upload Certificate and upload the certificate files provided to you by the CA. You can also drag and drop the certificate files into the specified area on the form.
If your CA has given you an intermediate certificate (for example, secure.domainname_ca.crt) as well as the SSL certificate (for example, secure.domainname.crt), make sure you select all the files at the same time during upload. You cannot upload them one at a time.
The only files you can select when setting up your domains are certificate files with the following extensions:
.pem. Files with extensions such as
.p12 do not work.
Deploy the domain as described in Deploy your Domain.
Do not delete (disable) an existing certificate until the new domain certificate deploys. Otherwise you may have an interruption in service.