Every particule and objects has a will/Haki that can be overwhelmed..
And as such..
CoA is manipulating your aura inward..
CoC is projecting your aura outward..
CoO is sensing auras in general..
1. Literally have an example of internal destruction and sentormaru armament haki air fists so that's an example of coA being manipulated outward. To add since internal destruction ryou has to be projected out of one's body into someone or something else to cause destruction that is a perfect example if it being inward and outward
2. We have an example of doffy being able to unfreeze himself quicker with the use of coC so thats example of coC being used inward lol
3. If voice of all things falls into the coO category then you can also project your haki outward and inward to be sensed by others to the point of having a diaolgue wiith someone while unconscious as shown by luffy.