LyX's interface appears to be similar to the one of many WYSIWYG word processors out there, but on a closer look you will observe that you don't have font style and size selection boxes, nor text format or alignment buttons. That fits in with the Lyx editing philosophy that "what you see is what you mean." When you say that you want to add a title to your document, you don't mean "a text that is centered and has a larger font size," you mean just that – a title – and all you have to do is pick the "Title" style from the box and start writing. The same goes for paragraphs, sections, lists and just about any other text element that you can think of.
Comments