My response to that—being from a teaching background—is that you could approach this whole area better. It sounds like you are trying to learn CSS layouts from all the random tips and discussions spread far and wide across the web. While these resources are great, they are not designed to provide a comprehensive, well-structured introduction to a subject. In my view, that’s where books come into their own. A well-written book will take you step-by-step through a subject like CSS, building up concepts on a solid foundation. Then you can go searching online and build on your understanding with the basic framework in place. Without that, you can end up all at sea.
For lay people such as myself it’s best to give a SIMPLE SYNTAX example. We are not designing NASA quality Internet sites to start with … Suggestions are always given without the benefit of WHERE in the CSS page the code belongs.
You can always specify your level of skill when asking a question. If people here explained where CSS rules go every time they answered a post, things would get quite tedious and repetitive. And we are all lay people, really.