The Marauders without Peter but Lily are supposed to wait in dumbledores office but they saw a timeturner and played with it just lily said its not a good idea - it wasnt, everything spun and now they are in 1995. Dumbledore was in his office and stayed calm and explainend everything and also that lily, james and sirius have childrens here. Also that they died and stuff. He gave them all fake names and said until the timeturner is fixed they beed to attempt to these classes. They’re allowed to tell us - their children.