Content Types are entities you place on the page for content
Digital Style Guide
Getting Started - Adding to Pages
Advanced Grid Wrappers are containers that hold Content Types. AGWs help hold content within specific widths. It is also where cards can be placed to sit in rows.
Enhancing Pages
Many Content Types have the ability to add animation upon scroll.
Image Guidelines can help in what size image to upload. It also provides links to help decrease image sizes.
Custom Formats provides text styles not provided in the general TinyMce formatting box options.
Note about viewing Preview pages
When looking at the Content Types placed on a page, the type of Content Type (which sits below the named item) now has a link (example below is General Content Block link). Make sure to not click this link, as it goes directly to the Content Type page to universally make edits.