All the data for these additional tables are already available in the current data table. So instead of calling the REST API again, we can duplicate the table we already transformed, into a new table. This is done by right-clicking on the table in the "Queries" pane (which is on the left side of the screen) and select "Duplicate". In this example we can create two duplicates, one for the order details and one for the notes.
Next, we can further transform each data table separately, so it only contains the data related to this table.
In the "Queries" pane, click on the first table. In the "Query Settings" pane (on the right side of the screen), you can rename the table to a proper name. I.e. "Orders", "OrderDetails" and "Notes". Next, we can start optimizing the tables by only using the columns that are related to this table and that's required for the report. If the "Orders" table contains i.e. some customer information which isn't required in the report, the columns can be removed as well. If they are required later, the columns can be added again by clicking on the cog icon next to the corresponding "Applied step".
To remove the columns, you press the "Choose columns" button on the "Home" toolbar tab. This shows a new dialog that allows you to select the columns you want to keep. Click the "OK" button to reduce the data table.
The "Orders" data table is now reduced to: