OK, what do I do here?

Hint 1 of 9:

Find a way of extending the edge of the precipice

Hint 2 of 9:

You must activate a device in the skull

Hint 3 of 9:

Place the copper ball in the skull's eye socket

Hint 4 of 9:

Oil the lever

Hint 5 of 9:

Melt the lard in the cauldron