keeping the object of meditation same, Samatha leads to calm and tranquility of mind and Vipassana leads to insight into nature of
The above is incorrect. Samatha & vipassana are not "techniques". I encourage you to free your mind from the wrong terminology you have previously learned. I will rephrase what you wrote, below:
keeping the object of meditation same, Samatha is calm and tranquility of mind and Vipassana is insight into nature of reality.
Thus, by merely observing the breathing with equanimity, the breathing will calm (because the mind has equanimity and is no longer thinking). This feeling of calmness is called samatha.
Also, by merely observing the breathing with equanimity, it will be automatically seen, if the mind is sensitive & clear enough, the breathing is impermanent and not-self. This clearly seeing of impermanence & not-self is vipassana.
Also, by merely observing the breathing with equanimity, if the mind is sensitive & clear enough, it will be clearly discerned wholesome states of mind cause the breathing to calm and unwholesome states of mind cause the breathing to become agitated & stressed. This clearly seeing of cause & effect regarding the relationship between the mind, breath & body is vipassana.
If I focus on the breath or if my object of meditation is bearth while meditation, what is the exact technique for both Samatha and
There is no technique, apart from keeping the mind clear and knowing the breathing. Samatha & vipassana are "fruits" of practise; wbich arise automatically. They are not a practise in themselves. To quote:
Thus for him, having thus developed the noble eightfold path... for him these two qualities occur in tandem: tranquillity & insight
Again, AN 4.41 describes four fruits from developing concentration. To quote:
Monks, these are the four developments of concentration. Which four? There is the development of concentration that, when developed &
pursued, leads to a pleasant abiding in the here & now (samatha). There is the
development of concentration that, when developed & pursued, leads to
the attainment of knowing & seeing (psychic power). There is the development of
concentration that, when developed & pursued, leads to mindfulness &
clear comprehension (perfect clarity). There is the development of concentration that, when
developed & pursued, leads to the ending of the effluents (vipassana).
The translator Bhikkhu Thanissaro comments about AN 4.41:
The Buddha explains how concentration, when fully developed, can bring about any one of four different desirable results.
Imagine growing fruit on a tree. The "technique" is digging soil, plant the tree, watering it, removing insects, adding fertilizer, etc. But the fruit grows by itself. You can do nothing to create the fruit. It is the tree that automatically brings forth fruit, when the tree is ready.
Sorry, the answers to question does not mention the technique or what exactly to do. Also google search results are showing up magazine articles.
Meditation is letting go & being quiet and still. It is not some type of manipulative exercise. I recommend to give up this idea of "technique".
References to suttas appreciated.