How Left and Right Hemisphere works

To understand this, take an example of a bird picking up grain of corn in forest. Bird needs to do two things simulatenously:

1. Focus on the targeted grain and understand what needs to be done;
2. At same time it needs to also focus on things which are broader like danger of other animals, otherwise it will be a lunch of someone else. 

So in this case while piecemeal/fragmented approach is coming from left side hemisphere, awareness of larger picture/broad/vigilant is due to right side and two hemispheres are connected via Corpus Collasum which passes info back and forth more like traffic signal.