This is a vast subject to cover. You will find it on auromaa in the audio talk of RE 031.
Briefly however the first important transformation is the psychic transformation. It takes place as the hidden psychic entity is discovered through concentration in the heart and growth of faith, love, devotion and surrender to the Mother. As the consciousness gets centered in and identified with the psychic being it begins to govern our thoughts and feelings and will and actions towards the Divine, towards the light and the right. Deepening further it can open the doors of the higher spiritual planes as the mind grows quiet. With the quietude and concentration in the head and above head, there is the descent of higher and higher states of consciousness bringing peace, light, wideness, purity, strength, Ananda etc. These mould the thoughts, emotions, will and action more and more in terms of the higher godlike consciousness. The consciousness becomes wide and there is a perception of the Divine in everything and everywhere. Finally after a sufficient purity, wideness, peace is settled the supramental transformation begins so that all in us right down to the physical expresses and manifests the Divine.
You will find further details in the chapter by the same name in The Life Divine which is a must read.
Affectionately,
Alok Da
