How to implement heap sort? [Solved]

Question

What am I missing in my heapify stage of heap sort algo? First index should hold the maximum value after heapifying stage but it doesn't happens in my case , any help is appreciated

https://code.sololearn.com/c7PdG0Ga1AGE/?ref=app

Edit:by mistake I was checking for if a[left]>a[index] tho it should be a[left]>a[largest]

Answer 1

https://youtu.be/HqPJF2L5h9U
I think this will help

Answer 2

Adarsh Kunwar thks!