At the Lake.. Kind of lost on where to go

[Muton]

I did everything I could around the lake.. The gold pointer points to a Mural cave, which I dont know what Im supposed to do there.. And some Shrines around the area with several buttons that can be pushed down. Not sure what to do there either

[DroneBoat]

Look around Shrine area, there are some painted symbols, some require specific point of view

[[-iD-]]

look for yellow paint, its everywhere or white, some times its white.

[dethtrain]

When you solve these 2 button consoles you'll get 2 gargoyle looking heads. Take them back to where you first saw the church key and put each head on the pedestal to progress through the story