This is a screen shot of point of sale interface. I want to update this page, then where i have to change? i mean which file py or xml. i think xml, because it is a view page.

Products are in kanban view here, i want to add no.of quantity here, like amount in the image. How can i add?

I dont want to select zero(0) quantity products in this interface?

How can i implement above to question?