The Screencast recorder is only available for Chrome. When you are signed-in to your Presentations2Go video server and your organization enabled this feature, you will see the record button in My Media.
If you use Chrome you can install an extensions (Screencast Recorder) from this link. To install the extension, click on Add to Chrome
You will be prompted if you want to install this extension.
If you click "Add extension", it will be installed.
Right after installing the extension, a setup wizard will guide you through the configuration steps.