I suggest you start by working right through a good tutorial such as
railstutorial.org, (wihch is free to use online) which will show you
the basics of Rails. Then work out roughly what pages you need you
need in your website and start building the bits you know how to
build. If you can't see how to do something and google does not throw
up any useful suggestions then come back and ask about the specific
issue you are having trouble with.
Colin