In the process of meditation we must learn to explore our minds so that the mantra may be used effectively. The first stage of meditation is to clear the mind. It is essential to observe the thinking process and witness the contents of our minds. Thoughts will appear and disappear, but always learn to be a witness. Do not identify with thoughts, images and symbols. In this way we will learn which of our thinking processes are helpful and which are harmful. Always recall that our train of thoughts is our own product; it is our own direct creation and that is why it affects us. It is at this point in meditation training that a mantra becomes invaluable. The mantra is like a seed, and we are like the soil. The mantra needs time to grow. The mantra must be nourished. Persevere in repeating it mentally and silently within and slowly a new object will grow and come to occupy the mind. Eventually instead of watching our thoughts we will begin to watch ourselves repeating our mantra.
Upaasana is dhyaana or concentration of meditation. A form is required for concentration. Reality is always the same and changeless. God, as the Ultimate Reality, is Formless. But Upasana of a Form is done with a purpose, namely, the attainment of a given benefit. The purpose to be attained by worshipping or concentrating on a Form differs. The scriptures tell you how to meditate and on what all Forms and with what results. For Upasana, you have to follow the Sastras or Scriptures. The different upasanas are all aids in the path to the ultimate goal, namely, understanding Reality. Scriptures prescribe Upaasana in order to train the mind to concentrate. Upasana is the affair of the individual; there is nothing collective about it