The Sub-level template is useful when structuring an interior hub for a project. Not quite a Primary template, but there is room to add multiple Sections that route the user to other details. The Sub-level template is great for defining your project's tent-pole features. The template allows easy expansion of the design through components.
Components
General purpose flexible box layout. This supports many, but not all, of the flexbox capabilities.
An annotated summary of something. This could be used on a home/marketing page to provide snippets of content that the user can click through for more detail. Or, as search result items. All properties are optional and can be mixed and matched as needed.
Put things at the bottom.
Combines Title and Menu elements responsively.
A Hero image or video, overlaid with text.
A grid of items. The preferred method of populating Tiles is to use Tile children.