A Container is like a folder in a hierarchy.
There can be multiple Items in a container, such as Promos, Content Blocks, Sidebars, and other Items that are considered children of the Item. A Primary Item will serve as the container for the Secondary Items, the Secondary for the Tertiary Items and the Tertiary for the Quaternary Items.
Individual files, such as media, which include image files, video files, audio files etc. are housed in separate media folders, but can be affiliated with any Item.