extjs6-classic

I am trying to learn ExtJS and am sort of stuck at a place. I want to create a screen with a grid on top and a form at the bottom. I want to bind them both with each other so that when I select a row from Grid, the form fields are populated (with the same record in the grid) and when I change anything in either grid or form, the other side is updated. So far, I have a view with a grid and a form. I have a store that provides data to the grid. I am stuck here. How to do two way binding between form and grid. I tried google and found a few samples here and here but they all are one way binding.