You've just wrapped your head around the idea of a vertical leg, might be getting better acquainted with the idea of a neutral pelvis - and now she wants to add a vertical sternum!
It's ok, take a deep breath and go easy on yourself - nobdody absorbs all of this information in one go, but the more you work with the different aspects of alignment (along with their supporting exercises) the more it all makes sense. Especially when you start to feel so much better and stronger.
Please be patient. Tissue takes time to respond and consistency is the key to success, not force.
We've considered our alignment in some detail from feet to hips. Now we go onwards and upwards - with the key player here being the ribcage. Many of us have very tight legs and shoulders and, as a result, an exaggerated Kyphotic curve in the upper back. We unconsciously disguise this by 'thrusting' our ribcage forward - creating a muscle sheer that weakens our core, stresses our spine and throws off our alignment. A huge number of modern diseases and chronic pain conditions can find at least some relationship to this movement habit. Your spinal chord is definitely stressed by this movement and that means your nervous system is also involved (even things as common as headaches and foggy brain can be resolved by discontinuing your subscription to rib-thrusting!).
THE EXERCISES ARE BOTH THE CORRECTIVE AND THE ASSESSMENT TOOL AT THE SAME TIME.
One of the keys to correcting this situation is to recognise it - but it's also important to lengthen the tight muscles in the back of the legs and the chest, while strengthening the lateral hip muscles - this means we have access to the tissue length and the strength to stand tall without pushing the ribs out in front.