Tiles in a grid section may be categorized in many different ways, based on the site creators, or viewers', need or preference.
Videos may be tagged according to the duration, popularity, resolution, suggested audience, creators, or features of the content, while the headshots in a team or organization section, or subpage, may be categorized based on the practice, role, title, location, department, seniority, or affiliations, of the resource.
These content categorizations are accomplished by tagging the tiles, while the tags are created by setting up a filter category. At least one category must be setup for the filter to be made available in a grid section, and for a tile to be tagged.
In this other article, you'll see how a category can be setup for a section, while this article gives the steps how a tile can be tagged with the available categorization. Design customizations for the grid section filter are done in the theme.