Complex sentence: When Shiva does not appear before him, Ravana begins to cut off his head, wherein a new head takes form out of his yogic power ghe continues meditating again for a thousand days, then cutting another.
Split into simpler sentences: When Shiva does not appear before him, Ravana begins to cut off his head, wherein a new head takes form out of his yogic power. He continues meditating again for a thousand days, then cutting another.