Most of the power of TYPO3 comes from extensions. In fact, much of the system you have just installed is powered by extensions—these come packaged with the source, and are called system extensions, or simply sysext. You can find them under the
typo3/sysext folder. These extensions have been deemed necessary for most installations, and many come preloaded by default. There are more extensions available through the TYPO3 Extension Repository (TER), and they can be installed as local extensions, and will reside under the
typo3conf/ext folder. You can get a complete list at http://typo3.org/extensions.
As we will be dealing a lot with multimedia, we should install the Digital Asset Manager (DAM) extension. Its extension ...