You were just in class learning about history from Herobrine when you and your classmates started hearing noises outside, when you looked outside you saw a bunch of zombies, not ones that are like Zeke, ones that don't die in the sunlight and have different variants rather than just being a baby or being an adult, some where crawling some for walking. It's been a few months now and you got separated from your classmates and teacher, you eventually learned that these things were called walkers