Log into the Ensim web interface as the Site Administrator, and pick the site which you want to manage. Once you've chosen the site which needs certificate, click "Services".
Then, click on the "Actions" pencil icon next to "Apache Web Server" and choose "SSL Settings" from the top option bar.
You will see a key, request, and self-signed certificate on the page at this point. Now, open the ZIP file that you received from us and extract the .cer file. Open that .cer file in a suitable text editor, such as notepad. Copy the entire text - including the top and bottom dashed lines.
Within Ensim, click "Import" and then paste in the certificate which you just copied to the clipboard. Click "Save", and then logout of the web interface.
Just in case something is wrong in the configuration file, we recommend backing up your site file so that you can switch back quickly if there is a problem.
To complete the installation, simply restart Apache.