How do i get Classic Environment for mac to play computer games?

Hi, when i was little i was obsessed with "Putt-Putt Saves The Zoo" the video game by Humongous Entertainment. And my mother got it for me as a present. But when i loaded on it i cicked on the game, and it said "You can not open the application "Putt-Putt Saves The Zoo" because Classic Environment is no longer supported? I have a mac laptop. Any help with how to install it, would be amazing. Thanks so much in advance! :)