I'd like to add several categories: sports, music, technology, and nature. Then, on the main page, I'd like to display two articles from each category. One column: sports. Second column: music. Third column: technology. Fourth column: nature. There could be two columns (two grids) and then the next categories below them (or something like that).

Now, when I add a new entry to a given category, it will immediately replace the oldest one on the main page for that category.

How do I do this on the main page? Right now, the main page displays the newest entry or places all entries from each category one below the other.