The term instance is used in the context of data according to a schema. As a schema defines a set of data types, an instance is a data object of a certain type.
As an example, given a type person defined in a schema,...
...an instance of the type has data structured according to the type definition, for instance as in the example below:
When loading a source data set in hale studio, the data is partitioned into instances. Those instances can be inspected in the Source Data view. When a mapping/alignment is defined, the transformation is executed on the source instances, creating a data set of transformed instances according to the mapped target types. These instances in turn can be inspected in the Transformed Data view.