Dashboards are more generic, and it isn’t possible to add a specific Topic. However, you can add a Category and display Topics of that Category. In order to do this, create a Dashboard Rule, and select the desired Dashlets from the Palette e.g Topics chart. Then go to your chosen Category, click Edit, and select the Dashboard you just created from the Dashboard combo, and save. Finally, go to Boards, and select the Dashboard you created.