Once you have completed the main story quests and reached Adventure Rank 12 you will be able to pick up the Adventurer’s Handbook by visiting Katheryne Mondstadt who you will be able to find near the entrance by the compass symbol. It is recommended that you pick up the Adventurer’s Handbook as doing so will help you to earn Adventure Ranks faster. The Adventurer’s Handbook also enables you to track everything you do and rewards you for completing those activities with various items and Adventure Rank XP.