If the host has enabled access for IE and Safari and you're on either, you will see a screen like this:
You will need to download the plugin before entering the webinar. When on the webinar page, click the dropdown link that says INSTALL NOW or DOWNLOAD PLUGIN (see above). After installation, you will need to REFRESH THE PAGE.
If you are downloading the plugin directly from the Temasys website, you will see two options DOWNLOAD (WIN) for Internet Explorer and DOWNLOAD (MAC) for Safari (see below).