Product page add/minus buttons, & number of items added

hey all,

Im building an ecommerce website, the product page have on each product a default “+” sign inorder to add to cart, I want to add another button next to it wit the ” – ” sign inorder to deduct the item from the cart incase the customer doesnt want it anymore. So instead of enterting the cart and deleteing the item, they can do it from the product page it self.

Another thing i would like to add is, when the customer clicks the “+” on the product page on an item, a number will appear on the item picture presenting how many its of this product has been added to the cart.

These features are avialble on this website and i would like to duplicate it: https://trolley.ae/

Thanks for your help in advance