Note that this tutorial is outdated for Modern food blogs which should be using the Modern Categories from the Feast Plugin. This allows us to automatically configure the posts per page to optimize your site for SEO and user experience on your behalf.
The category pages, search pages and archive pages are all controlled by a single location.
You can navigate to Settings > Reading > Blog Pages > Show at Most to control the number of posts that show up on your archive pages.
Make sure to fill out your category pages with content!