That alone is Real which exists by itself, which reveals itself by itself and which is eternal and unchanging.

The search "Who am I"...ends in the annihilation of the illusory "I" and the Self which remains over will be as clear as a gooseberry in the palm of one's hand.

All that is required to realise the Self is to “Be Still.

Apart from the body does the world exist? Has anyone seen the world without the body?

Concentration is not thinking of one thing. On the contrary, it is excluding all thoughts, since all thoughts obstruct the sense of one's true being. All efforts are to be directed simply to removing the veil of ignorance. Concentrating the mind solely on the Self will lead to happiness or bliss. Drawing in the thoughts, restraining them and preventing them from straying outwards is called detachment (vairagya). Fixing them in the Self is spiritual practice (sadhana). Concentrating on the heart is the same as concentrating on the Self. Heart is another name for Self.

Yogas chitta vritti nirodhah - (Yoga is to check the mind from changing) - which is acceptable to all. That is also the goal of all. The method is chosen according to one's own fitness. The goal for all is the same. Yet different names are given to the goal only to suit the process preliminary to reaching the goal. Bhakti, Yoga, Jnana are all the same.

Such happiness is relative and is better called pleasure or satisfaction.