1. The Topics page can only be accessed through the 'Admin Area' by administrators (#1 in the screenshot below).
2. Then select Topics from the left side panel (#2 in the screenshot below).
3. Search for the name of the Topic within the search bar (#3 in the screenshot below), or simply locate the name of the topic in the list.
4. Click on the Topic title - and a box will appear similar to the one below.
5. Click on the edit button (#5 in the screenshot above).
6. Update the form as necessary (see the instructions under Creating a Topic for more information) and click 'Save'.