I remember how I struggled with floats when taking the Intro to Web Design class. This topic was one of the most confusing ones to me. However…
…doing the floats challenges helped me to understand it a LOT! I can’t say that I totally get floats now, but these exercises made it much clearer to me. The best way to learn something is to practice it. Same thing I can say about Flexbox. At this point, I can not to mention how cool it was building a webpage according to a .psd file by using both floats and flexbox. The more I learn about HTML and CSS, the more I like it!
Finally, the article Getting Started with CSS Layout by Rachel Andrew is a great overview of CSS layout with a plenty of useful links and a great source to come back and refer to.