To answer your questions:
1) In this sense, "deconstruction of thoughts" means breaking down your thoughts into their most basic elements so that they can be better understood and be acted on more effectively. Deconstructing a thought involves thinking about the thought, why you may have it and whether it is has a productive or unproductive perspective. Often times, simply reflecting upon your thoughts and deconstructing them can lead to a new perspective or new insight about yourself or situation.
2) Externalization can help control mood swings and battle lack of motivation simply by the act of expressing yourself and your struggles in a form outside of your own head. Allowing yourself to record the details of your struggles can be a very relieving process that calms the mind (think diary). Additionally, having your thoughts and feelings externalized provides an access point for reflecting upon them at later times when you are more clear headed so you can be prepared for the next time you have those same thoughts or feelings.
Let me know if this answers your questions or would like to discuss in greater detail.