Each entry in the list of works cited is composed of facts common to most works—the MLA core elements. They are assembled in a specific order. Not all elements are present in each citation.
[taken from https://style.mla.org/works-cited-a-quick-guide/]
The concept of containers is crucial to MLA style. When the source being documented forms part of a larger whole, the larger whole can be thought of as a container that holds the source. For example, a short story may be contained in an anthology. The short story is the source, and the anthology is the container.
[taken from https://style.mla.org/works-cited-a-quick-guide/]
Marquette University's 4.5 minute video to explain MLA containers used in the 8th and 9th editions.