Models stored in the Data Model can be related to one another. A view in the Back Office can display the data of a model. Because Betty Blocks uses a relational data model, it is possible to navigate through your Back Office information by using subviews. The way a subview will appear in your Back Office depends on the relation between the models.
A form subview is created in your Back Office when the model relation between the current and selected model is set as belongs to. This means that one object from your model is related to one object from the target model. In this subview a from will appear where a single object can be seen and altered. More about forms can be found here: What are forms in the Back Office
A Grid subview will appear in your Back Office when the model relation between the current and selected model is set to a has many or has and belongs to many. This means that one object from your model is related to multiple objects from the target model. In this subview a Grid will appear which shows data from the related model, this Grid works the same as any other Grid. More about Grids can be found in this article: Grid Reference