Add to cart pop-up

[Sam_78]

Hi, I am trying to add a functionality where I need to add a pop-up when they add a product to their cart. Right now on phone there is no way new customer would know that product is added to their cart other than CSS color change. I just need help with which file to start editing with. I am planning to show the cart module when they click on add to cart button showing this is your cart now with button to continue shopping or checkout.