Magento 2.3.5 Add a popup when Add to cart button in product view is clicked

I’m using Magento 2.3.5 with Porto Theme.
This theme when add to cart button is clicked show only an alert message with a green background.
I need that when add to cart button is clicked a popup appear and show 2 buttons, Continue Shopping or Go to cart.

I tried to do it by following this Adding a modal after adding to cart but with no success.

Can anyone tell me how I could implement the popup in Magento 2?

Thanks