Mind

This is normal. The mind is always trained to move outwards, towards the world. It is just not easy to have the mind concentrate on something for a while.

Then how can concentration be achieved?

When we continue to chant the Maha Mantra, in due course of time, the power of the Divine Name will automatically give you the concentration that is required.
The elephant cannot keep its trunk stationary. It keeps swaying it always. In order to arrest its movement, the mahout gives it a huge chain to hold on to. Similarly, in order for the mind to concentrate, we have it focus on the divine Name and Form of the Lord. That is the basic principle of idol worship. Instead of going for a multitude of Names and Forms, it is advisable to stick to one deity and chant one Mantra incessantly. This will bring concentration and one-pointedness. One can thus achieve eternal bliss by merely chanting the Maha Mantra.
In Bhagavat Gita, Sri Krishna says I purify those devotees who worship me by way of chanting the Maha Mantra. So, by chanting the Maha Mantra, you are automatically purified and at the same time, get Sri Sri Swamiji's blessings too.
Chanting the Maha Mantra mechanically is the Sadhana. When this is continuously done, in due course, you will start chanting it while you enjoy the sweetness of it. This is the 'Sadhya' (the result which is Pure Bhakti).

Hence by merely chanting it will make the mind divert towards Bhakti. No additional 'sadhana' is requried for controlling the mind or diverting it.
The Body, Prana, Intellect – all of these are ‘Jada’ (lifeless). When the mind dies, it is simply not possible for one to identify oneself with these. When the mind dies (when one realizes), he doesn’t identify himself with the body, prana or the intellect (which are ‘jada’ or lifeless). It is so, only for others who view him as his body and its related sheaths.

Let us assume that you knock the door of a house and the householder asks who is at the door. You say, ‘Naan’! (me!). Again comes the question from inside, ‘Who is that?’ and you respond, ‘Naan thaan!’ (its me, myself) to make your identity clear.

Here you are mentioning two things – the first ‘Naan’ refers to your body, and the second ‘thaan’ refers to the Self. When you wish to make your identity clear, you unknowingly say ‘Naan thaan’, stressing on the ‘thaan’, the Self.

In this context, Ramana Bhagavan, in His Aksharamanamalai says, ‘Thaane Thaane Thaththuvam idanai thane kaattuvaai Arunaachalaa’ When the ‘Thaan’ (Self) reveals its presence, the ‘Naan’ (body) is no more significant and the memories, intellect, body etc. which are all related to the latter don’t exist anymore