You should start from HTML. That is the basis for all the others. CSS is a language that will help you create the design of your website without using tables. (it has many other advantages) But, even if you don't know CSS you can still build websites. Without HTML you can't do anything with CSS.
If you want to learn HTML check out my hub:
I also have another hum related with that one that is the introduction to build a website that might also be useful to you.
Hope this helps