To create a mapping in SQL ELT mode, you create a mapping, and then select

Mapping - SQL ELT

as the mapping type. You are then prompted to choose a

Google BigQuery

target connection. If your organization doesn't have any

Google BigQuery V2

connection, you are prompted to create one. After you choose the target connection, the Mapping Designer opens. When you create a mapping, a Source transformation and a Target transformation are already on the canvas for you to configure.