The reference manual for each type or variation of QueryGrid describes considerations and limitations in their introductions. These should ideally be studied before making use of the feature.
For Teradata-to-Aster QueryGrid, you must type in the Aster table name in the Tables combo box and then press the Tab key to load the columns for that table. This is because the QueryGrid Help Foreign Database on Aster returns only the Schemas in an Aster database. There is currently no way to retrieve the Aster tables for a schema.