In plain words
The second girl answers: He dammed the sea, dark with its depth, entered Laṅkā, cut off the golden-crowned heads, nine and one [all ten], of Rāvaṇa, who did not reckon with his valour, and gave a lasting kingdom to Rāvaṇa's own younger brother [Vibhīṣaṇa]. Sing of the nectar one never has enough of, and leap! Sing of the king of the people of Ayōdhyā, and leap!