When you get into your blog, there should be a pencil to the right top. Click on that, that allows you to edit your blog
First you need to create your categories. After you have done that, click that pencil, then click ADVANCED. You will be able to choose the category that you have created.
To create a category, on the right side of the page, there is pencil above the box that shows categories. Any that you create will show up in the advanced editing. Click the one you want and save changes.
Took me a minute to figure all that out
