ICON THEME - How to add an "add to cart" button

[Stauny]

Hi there, I'm looking to add an "add to cart" button to all my products in collection. Currently I have a "quick view" button but I'd like a "add to cart" button so customers can quickly add a product to their cart without having to quick view the product first or get redirected to the checkout. Preferably I want the customer to add to cart and continue shopping on the same page. I'm using the ICON THEME and have tried a few suggestions I've found on here but they haven't worked.

MY URL is vitalzing.com . https://vitalzing.com/

Thank you,
Staun