Hi! I'm Daniel, As a villager who didn't finish villager school I'm just gonna explain that, Every villager must have villager school, and it includes Building, Running, Mining, Resource gathering and Defense.
Let's start with building, During Building class you have to use the items that the instructors give you, then you have to build a house. It has to be safe from mobs such as zombies, Have the normal stuff that a normal house has such as crafting benches and work places and it has to have a working entrance like a door. Simple right? Well WRONG. The instructors will look at the design of the house, size of the house, and the interior and defenses of the house AND if you don't have enough resources, you will need to get it by yourself, cool right? I don't think it's cool.
Now for running, you may think "That's odd, why would running be a subject?" Well if you didn't guess it's because running is the MOST important subject, How does it work? During running class we have to run to the ruined portal near the village, it's 1000 blocks away, then you have to run ALL THE WAY BACK to the village, My math is bad I don't know how much blocks that is, we don't have math class. Running is important because if a zombie is following you, the best solution is to run away.
Mining. The most dangerous subject of all. During mining class the instructors give one iron pickaxe and a shulker box, but you have to buy the shulker boxes from the mayor of the village, Our instructors say that shulker boxes are from a dimension called "The end" which is why they cost 128 emeralds for one box. I don't believe those nonsense about those silly boxes. In mining class people are grouped into 2 for mining, mining is a bit boring if you ask me. Why is mining dangerous? Lava, zombies, creepers, skeletons and more.
Resource Gathering, It's mining but there's a real task like get 10 iron ingots or get 64 oak logs and stuff like that. So it's pretty boring. It's just that we get diamond pickaxes that are shiny, I don't know why though. Enchantment?
Defense, my favorite subject, We get to use wooden swords to attack things, sounds cool right? Kind of. We attack at our stands with zombie heads during class, last year when we had our tests we got to fight slimes! Where do we find slimes? Instructors will give us boats and we follow the instructors, we get to row BOATS! It's really fun.