hi, glad to help , three basic mistakes in ur sentence . 1 "随着“ means "according" so it doesnt make sense ,it should be "接着 （then) " , 2 missed one measure word ”场 “ for "rain" , 3 "跑一跑 ” is inappropriate , double verbs showing together normally means "try sth "that sort of meaning in Chinese , such as "看一看 （take a look )" " 尝一尝（ have a taste) " etc . so u should just say " 跑进 ” to express "run into ". So the whole corret sentence should be 天突然变黑了，接着下了一场大雨，大家都跑进学校里面了。