Complex sentence: Once she arrived home she put the clothes aside and put the board on top the vase to protect the water from dust and mosquitoes, she noticed a small figure in the board but she couldn't tell what it was.
Split into simpler sentences: Once she arrived home she put the clothes aside and put the board on top the vase to protect the water from dust and mosquitoes. Then, she noticed a small figure in the board but she couldn't tell what it was.