Ananta-rūpam means millions and millions. The Manu is also incarnation of Kṛṣṇa. So in one day of Brahmā there are fourteen Manus. So Brahmā lives for one hundred years. Just see how many incarnation of Manus are there even for one Brahmā, and there are innumerable Brahmās also. So, as stated in the Śrīmad-Bhāgavatam that nobody can count how many incarnations are there, but some of the chief incarnations are mentioned, and Lord Rāmacandra is one of them.
So Lord Rāmacandra, He killed Rāvaṇa and He installed his brother. His brother was devotee, Vibhīṣaṇa. So He did not go to conquer Ceylon, because He was emperor. He went to punish that culprit Rāvaṇa, and He installed his younger brother Vibhīṣaṇa in that . . . and He came back with Sītā, and again He was installed after fourteen years, and His brother was so faithful that so long His eldest brother was away, Rāmacandra requested him that, "Your mother wants that you should be king, and I also wish that in My absence you should be king."
Bharata, he was so faithful brother, he replied: "No. You are king. So long You are living, nobody can be king. So I cannot be king." Then He requested, "At least you must administer."