One of the most basic things to learn outside of manipulating text in css, is manipulation of tables. There is always a need to know how to place something in the right place with the right margins.
Thankfully, the World Wide Web Consortium has a page that helps you understand not only how tables work in HTML, but their respective counterparts in css. This gives you the chance to set up the css version of a table.
It’s always good to know the basics. While css isn’t rocket science, it does tend to become a bit convoluted when you’re just starting out and there’s a whole lot of things in a stylesheet that you’ve never tinkered with before. Just take one thing at a time and master one at a time. It doesn’t take too long to fly around in css otherwise.