Installing your SSL Web Server Certificate:
1. Login to the Plesk Control Panel.
2. Select 'Domains' from the left hand menu.
3. Click on the domain name that the certificate is for.
4. Click on the 'Certificates' menu item.

5. There is a button in the middle of the page labeled 'Browse'. Click 'Browse' and navigate to the location of the certificate (save certificate into .txt) you received from RapidSSL. Select it, then select 'Send File', this will upload and attach the certificate to the corresponding private key.
6. The certificate name will now appear in the list of certificates at the bottom of the page.
7. Now click 'Up Level' from the top right of the screen and choose 'Setup'.

8. Uploading a CA certificate
For the your IPSCA Certificate you will receive what is called a CA Certificate,
or rootchain certificate. The CA Certificate is used to appropriately identify and authenticate the certificate
authority, which has issued your SSL certificate.
You may download the IPSCA bundle certificate here:
Intermediate Certificate (IPS-IPSCABUNDLE.CRT) in http://certs.ipsca.com/companyIPSipsCA/IPS-IPSCABUNDLE.CRT
To upload your CA Certificate, follow these steps:
8.1. At the certificate repository page, select a certificate from the list. You will be taken to the SSL certificate properties page.
8.2. Use the Browse button, within the section related to the certificate uploading, to locate the appropriate CA Certificate file.
You can upload an existing certificate in two ways:
8.2.1. Choose a file from the local network and click the Send File button (.TXT files only)
8.2.2. Paste the CA certificate text and private key into the text fields and click the Send Text button.
8.3. Click Send File. This will upload your CA Certificate into the repository.
9. At the top of the page, change the 'SSL Certificate' drop-down menu to the certificate you have just installed.

10. Click the 'Server' item from the left hand menu.
11. Click on the 'Service Management' menu item.

12. You now need to Stop and Start the Apache process.

NOTE: Restarting Apache will not work. You must stop and start the service to complete the installation and commit the changes.