Are you asking what the user interface and navigation should look
like, or how to get the UI that you have already defined? If you know
how the UI and navigation should function then the answer should be
fairly obvious. If you can obtain the functionality in a number of
ways and don't know which is best then just go for the one you feel
most confident with and if it ends up not right then change it. That
is the best way to learn when you are just beginning. The effort
involved in re-factoring should not be great. Make sure you have full
test coverage as you develop it so that you know it still works when
you have refactored.
I presume you have already worked right through a good tutorial such
as
railstutorial.org.
Colin