If you want to use Internet Explorer or older versions of Safari, you will be asked to install a plugin after your enter the meeting room.
Here is the process step-by-step for Internet Explorer:
Click to download Internet Explorer plugin:

Click "install" from the top of your screen:

Click "run" to start the programme in your computer:

Click "install" to proceed with installing:

When you click to install the plugin, you will see this screen:
Go to "Manage Add-ons"
Here you select the "Temasys Communications Pte Ltd" plugin, and click on "Enable"
Refresh the page, and you can enter the meeting.
Enjoy!