Go to the right end of the village.
Look for where there's a rock that has wood arrangement pass the tents and the hanging-drying area.
Turn around from there and cross the marsh to another island.
As soon as you get there - pan right to the reeds and look for the active spot.
It will look like this - this is where you click to get back to 1912. Be sure to wear your goggles:
This is Graham's description as to get back:
face the fire, go forwards twice to the waters edge, turn right, forwards, turn left, forwards three times and look right. Use your goggles to get back to 1912.