I need help, and some education. I have been through all the tutorials in the Joomla beginner’s guide. I have a pretty good understanding of what modules are, what sections are, what categories are, and what content is and that the menus are what control everything.

What I want to create is a customer portal.
For example:
A customer can log into their bank account and only see there account information and no-one else’s. That's the kind of content management system I want to create. The only difference is I want my customers to be able to log into their area and upload and/or download content as needed; only the secure content from their area and no one else’s. They would not be able to view any of my other customers secure information.

I would also like to have public static pages, and blog pages available to all. I understand how to create the later; it’s the former than I am having difficulty in understanding how to do in Joomla. Any help would be greatly appreciated. PS, my coding skills are basically non existent. I know enough XHTML, MySQL and PHP to be dangerous.