The final view in the anatomical series is the arch view. Keep your probe where it was for the ductal view, but now rotate it around 450 clockwise. The marker should now be pointing towards the patient's left shoulder. This is one of the hardest views to acquire, and often requires a repositioning of the probe to the right or left of the sternum. Having the patient's head extended, e.g. by putting a roll under the neck, often helps.
In theory you should be able to see the full length of the arch (round to the left subclavian artery) on a single view:
It's important to see right round to the left subclavian as most coarctations occur at this point. Colour Doppler can be very helpful to look for turbulent flow at the point of a potential coarctation. Flow should look laminar: