Topics in the Second Brain template would be what the PARA method would refer to as Resources, as defined as "Topics or interests that may be useful in the future." Hence, Topics are what your Notes and References can be tagged to and where you can retrieve your Notes and References when you open up the relevant Topic's page.
In our Second Brain template, you can create Topics under an Area. For example, "Health and fitness" might be an Area, while "Nutrition" and "Exercise" could be the two Topics under Health and Fitness. Articles and references related to Nutrition will be added to the References database and tagged to the Topic "Nutrition".