You can do quest every 24 hours, select the year you're interested and you see the number of mobs you need to kill and start it (there will be the timer).
If you'll satisfy the request, select the enchanted book and collect the reward(experience and gold). Obviously the higher level of monster is, the request will be higher and the reward will be bigger.
If you don't manage to accomplish the mission in 24 hours, it will reset.
As alternative, I thought you can do quests only for your year (example: you're on 5th year and you can do quests only of that year)
If you'll satisfy the request, select the enchanted book and collect the reward(experience and gold). Obviously the higher level of monster is, the request will be higher and the reward will be bigger.
If you don't manage to accomplish the mission in 24 hours, it will reset.
As alternative, I thought you can do quests only for your year (example: you're on 5th year and you can do quests only of that year)