Head towards the west end of the southern continent. When you get close, Galbadia Garden will attack. Select your orders from the list, ending with No Orders/End. On the 2nd floor, speak to anyone standing around. Go down to the the 1st floor and head to the Quad. Talk to Zell and your other teammates there.
When you return to the bridge the battle begins. Switching to Zell's team, head left to the edge of the Quad. When Rinoa falls off the edge, head back inside and go to the front gate. After meeting up with Squall, reform your party.
Head to the 2nd floor classroom where you'll have to fight 4 Paratroopers. After the battle, talk to the other students in the classroom. Return to the bridge and after your speech, go back to the 2nd floor. Head to the end of the corridor to find the missing kid. When the hover trooper knocks you against the wall, examine the hatch, look for another option, then press the button for the emergency exit. Mash the buttons to knock the trooper off and then after rescuing Rinoa, run left to reach safety. Name the creature on your ring then go inside.
Head right, right again and then up the stairs until you see Raijin and Fujin. Go left and enter the first door on the right. Talk to the student there to receive Key Card . Go back to the save point where you came in and go left this time. Your Key Card will allow you to enter the left door.
Cross the hockey rink and leave through the door to the far right. Enter the door on the right of the the hall and speak to the student there to receive Key Card . Go back to the save point where you came in again. Go back up the steps, past Raijin and Fujin and keep going up. Once outside, jump down to the courtyard and continue going left. Go south, past some stairs until you come to the main hall. Approach the creature in the center to fight Cerberus. After defeating it, you will gain Cerberus GF.
Take the southwest passage and go in the door on the left. The student there gives you Key Card . Return the way you came until you find the stairs you didn't go up. Go up them now and make a left to find the elevator. Use the Key Card to access it. Approach the Sorceress to fight Seifer (II).
Go back down the elevator and head back to the stairs, but go right this time. Circle around the balcony and enter the auditorium on the right. Approach the podium to fight Seifer (III) again. Once he falls, you'll fight Edea (II) directly. You can Draw Alexander from her.