We now need to re-arrange the axes so that the B Axis is mounted in the X Axis and the X Axis is mounted on the Y Axis.
In the Machine Tree:
Drag the Y Axis onto the Z Axis.
Drag the X Axis onto the Y Axis.
Drag the B Axis onto the X Axis.
Here is the final Machine Tree layout:

To confirm that correct movement (kinematics) of the ATC:
Select the B
Axis and use the Position slider to check the rotation. Repeat
for the Y Axis. Only the ATC should
rotate around the B Axis and both the ATC and its holder should move along
the Y Axis.