How do i show/hide page content depending on the users role?
There are two good ways you could go about this.


Install Panels and
enable Page manager. Panels has a huge collection of what are called
'visibility rules' for individual panes. These allow you extremely
fine grained control over who sees what portion of the page. Panels
offers a lot of power, but brings a lot of complexity along with it.
Put your messages each in their own block. Blocks come with the ability to show and hide for certain roles.
This method is much simpler, but if you have a lot more content than just
the welcome message you want to show and hide panels
will end up being a more customizable solution.