In addition to categories, you can also assign authors to content. Beyond answering the obvious "who wrote it?", assigning an author could be useful - for example - if a visitor wanted to find all posts written by a specific person. Like many things in HiFi, how authors will affect the layout depends on how the developer set up the website.
How to add a new author
Under the main Website tab, click on the Authors tab (as shown above). The Add Author button speaks for itself.
How to assign an author to content
Once you have created an an author, you can add him or her to content by clicking on the Show Publishing Details link while on the content page in question.
Doing so reveals some extra content options. Click the Add An Author button. A drop down menu will appear from which you can select authors that were defined under the Authors tab covered earlier. Note that you can add multiple authors if needed.
Make sure to hit the big green Save Page button once you're done.