Login to the VMware View Administrator console, navigate to "View Configuration | Servers", select the "Connection Server" tab and select the connection server you want to configure. Now, click the "Edit" button then select the "Authentication" tab in the popup window.

To switch on two-factor authentication, select "RADIUS" in the "2-factor authentication" drop down list. Then select "Create new authenticator" in the "Authenticator" option:

Click "Next", and click "Finish"

You might also want to enable the "Enforce 2-factor and Windows user name matching" option for extra security.