Можете пожалуйста проверить по грамматике. Все замечания и предложения…

Можете пожалуйста проверить по грамматике. Все замечания и предложения приветствуются. I hang out with friends at my house. Suddenly, the manknocked at the door. He said: "I lives in a flat upstairs." He was terrified by something,and then he started panic, and… walk off. It was late at night, we with friends were really terrified! . But then I understood that I live on the 5th floor of five floor houses… it is frightening.