Actually, a ship with a Continuum Distortion Drive doesn't actually need to turn to navigate. Most of the movements done are actually translations: you can move just as much in full reverse as you can move to the side.
You have three reasons, however, why you want to change the ship's facing. The first is to take advantage of your fixed, mostly forward-facing sensors. The second is to expose different areas of a ship's hull to enemy damage; to hopefully protect damaged area and spread the harm done to the ship's armor to insure longer running time at peak performance in a battle. The third is to take advantage of your firing arc, namely the most powerful weapons generally being front-facing.
As to how turning works... either you do it through the CDD/CFS with the drawbacks Vesper pointed out, that you do it with your gravimetric engines or through your maneuvering jets. All still work inside the CFS bubble.