Figma tutorial: Prototype with variables - AI Video Analysis

The video introduces advanced prototyping in Figma by leveraging variables, beginning with a practical example of managing product availability on a farm-fresh shop page [0:00-1:30]. The core interaction demonstrated is decrementing the "amount available" of watermelons each time the "Add to cart" button is clicked [1:30-2:00]. This is achieved by first creating a local number variable titled "Amount available" and applying it to the corresponding text layer [2:00-3:00]. The prototype is then set up so that clicking the "Add to cart" button triggers a "Set variable" action, subtracting 1 from the "Amount available" variable [3:00-3:30].