The Corrosion 105 Light Guiding ceremony is located South of the Three Realms Gateway. You will most likely see on the map that that area has a Corrosion Intensity of 105.
You are needed to do some quests to remove the Corrosion, but we are here today for solving the Light Guiding Ceremony Mirror Puzzle in Corrosion 105 to get the common chest and grab the loot.
Corrosion 105 Light Guiding Ceremony Mirror Puzzle – Genshin Impact
The location of the Light guiding mirror puzzle is located in the middle of the island, right next to the marked area on the map.

So the puzzle contains 4 mirrors and you are needed to align them perfectly so they guide the light towards the end area, which is a levitating orb that can be activated only if the light hits it.

You need to form an upside-down form of the letter “C” to guide the light to the right destination. Once you have made the pattern with the mirrors, shoot your shot with the light and unlock that chest!