《Day of zombie》 has many chapters and each chapter has many stages. You will need to eliminate all enemies to pass the current stage and challenge the next one. 

　　You could challenge the same stage again after you have cleared one to achieve three-star assessment to get resources, such as, Diamond, Skill Book, and Experiences. Later stages will grant more resources.

　　We suggest you to improve your army before encountering powerful and outmatched army. An appropriate formation is the key to defeat matched opponents. An appropriate positioning is another key to defeat matched opponents. Commander will learn those techniques from continious playing or reading tips.