When the song maker is on, creators on a plan that includes it see Make a song in the creator menu. Give the song a title, a style, what it is about and your lyrics (or let the AI write them), and press Make the song.
It usually takes a few minutes. The finished song lands in your drafts as a single, with the service named as its AI tool. Listen to it, add a cover, then publish it like any upload. Your plan shows how many songs you can make each month.