Your ordinary IP address, as provided by your Internet Service Provider (ISP) doesn’t change.
Winston adds an overlay network to your internet connection. So, your connection to websites you visit is routed through any one of 20-30 other Winstons on the Winston Peer-to-Peer network, and it changes every 10 minutes. Those websites’ tracking systems log a different IP (“exit point”) depending on the Winston through which your data is routed, anonymizing your activity.
Note that if Winston is behind a firewall and/or port 7776 and 7777 is blocked, fewer exit points are available, so your apparent IP address will not change as frequently. For more information about port forwarding, please visit this article.