There are five main areas where you can see any new responses highlighted as per the screenshots below.
When you login to your web account, you will see an icon attached to the Forms menu heading denoting the number of responses you have not yet viewed.
This notification icon is also shown when you are looking at your dashboard within the most active forms section.
You can also see variations of this icon on the Forms list on a per survey form basis as well.
When you open the Form responses page, the small orange dot denotes any new responses awaiting your attention. These are automatically marked as viewed when you have checked the response.
Finally, if you receive any further responses while you are logged into your website account, you will receive a notification beside your name at the top right of the page.