You don't have to recommend an author or story and a reviewer if you don't want to. You can submit either an author/story or a reviewer if that is what you want to do. You can still make recommendations in both sections if that is what you want to do. Leave the boxes that you don't need to fill in as they are. It would be helpful if you could fill in all the boxes in your chosen section. The submit button covers both sections, you only need to click it once to send the information.
Recommend an Author or Story