The History Lesson - Side Quest Walkthrough
Dying Light 2 > Side Quests
1 - Reach the memorial square.
After getting the quest from the Teacher at Rooftop School, Trinity, head to the memorial square.
2 - Investigate the square. / Light a candle.
There are two plaques to investigate right in front of the monument. And, facing the monument, to the right, there are bullet holes in a tree.
Then light the candle at the marker's position.