Folklores
Kill Mistville "Residents," to get their eyes, which can be used to gain Infection Progress.
Dispel the mist at the cost of your Sanity and find the Clock Tower to start a new day.
Challenge Advent of Folklores to obtain Chests of Folklores.
Infection Progress
Mistville "Residents" will appear in the stage when "there are Mistville 'Residents' paying you a visit in this stage." Kill them to get their eyes, which can be used to gain Infection Progress. You will be able to visit Mistville upon reaching a certain Infection Progress.
Mistville Exploration
After entering Mistville, you will interact with a Lantern to start your exploration, during which you must dispel the mist at the cost of your Sanity and find the Clock Tower to start a new day. When your Sanity has been exhausted or you have survived 15 days, the current round will be over.
Advent of Folklores
On odd-numbered days. You can interact with the Clock Tower to enter the Advent of Folklores gameplay. Completing an Advent of Folklore will allow you to get rewards from a Chest of Folklores.