In the second aliyah Moshe tells Korach and his 250 followers in the rebellion to prepare a firepan and incense and present it before G-d. In addition, Korach goes around to all the Jewish people and incites them also against Moshe and Aharon. Everyone comes to the door of the tent of meeting and the Glory of G-d appears to them there. What happens then is in the next aliyah.