If you are completley new to Ror I would suggest reading some of the
thousands of tutorials on the web, or one of the several books about
Rails that are out now (Agile Web Development With Rails 2nd Edition
is the crowd favorite).
The answers to your questions aren't that simple. How does the
application know what user is logged in? You can search your database
Where 'username' is the column in the DB you want to search and 'Bob'
is what to search for. The entire row will be returned as an array
@user, so then you can use @user.location @user.first_name
@user.last_name or @user.whatever
Usually developers store the user_id in the session information, so
you can do something like @user = User.find(session[:id])
I hope this gets you on the right path, but you really need to start