how we can get calmness?

Answer 1

I can only speak for myself - I listen to soothing, rhythmic music or sounds; I close my eyes, or let them go unfocussed; I lie down or sit back and relax all my muscles; I repeat in my mind a simple phrase or a rhyme to keep my mind from thinking. These things usually work for me; you may find that similar methods, or some quite different, work for you.