Data Types Page
App Builder uses "code-first" approach for working with data. You create objects relevant to your domain as data types and you list object properties as data type fields. App Builder takes care of everything else. There is no need to think how data is stored or retrieved. Click on the Add new data type button to create a new data type or click on a type name to go to the Data Type Details page for editing its fields, views and actions.
When creating a data type, you have to choose the kind (or type family) it will belong to - Primitive, Embedded, Directory, Transient, Document, Report or Journal (the last 3 types are available only when you use the Professional package). It is possible to delete a data type by selecting it (ticking a row checkbox) and clicking the red Delete icon.
If you are not sure what type to choose, start with the Directory type and move to creating other data types later. You can read more about each data type here