Load sections of page content

I'm working on my first .net application and I have a pretty complex requirement.  I need to populate certain sections of content on a web page based on a user's security.  Sections can contain any amount of different .net controls - grid, checkboxes, textboxes, etc.  When a user visits a web pages, all sections are collapsed on page load.   if the user has access to a section, the section will become visible and the data will be populated.  If the user does not have access, then the section will remain collapsed.    I read on article on using user controls to load section of content on a page.  I've also read about web parts.  I'm new to .net and have to use web forms for the project.  I'm sure something like this is pretty common but I have no idea about where to start.  Can anyone offer a simple solution for this?  The goal is to only load data for the sections the user has access to.