About the back end (how things on the web site work)
The AEVA web site is run using a piece of software called Drupal. It is free and open-source and falls into a category of software called a CMS - a Content Management System. What it does is that it allows the content of the site to be created on the site itself. This means that anybody who has the permissions can make additions or changes to the web site.
Drupal by itself provides a pretty basic and uninteresting web site, but it allows modification of what it does through the use of add-on modules and themes. Modules are a way of providing extra features, and themes allow the 'look and feel' of the site to be changed.
One of the major modules installed on the AEVA web site is CiviCRM. "CiviCRM is a web-based, open source, Constituent Relationship Management (CRM) software geared toward meeting the needs of non-profit and other civic-sector organizations." It is used by AEVA to handle membership subscriptions, payments and access to web information.