Yoga Guru B.K.S. Iyengar on How Meditation Transforms You

meditation is awareness about your mind , thoughts and emotions. it's like a drone capturing footage of everything happening on ground (mind). the enemy ( bad thoughts) disappears once they see a drone is watching them. the drone is your real self also called the "observer".

His approach was only a asana, more like gymnastics, he said pranayam and dhyana will happen automatically, flawed and conflicts with shastra

I learned yoga from his work: Light on Yoga