I had seen how composers prepare for a songwriting contest. First is the rigid selection of existing compositions that is perfectly appropriate for the theme of the contest. And if there are no such song in the collection, they have to write a new one. When the song is ready, the minus one is checked and a good singer is invited to do the vocal part of the demo song. After a day or two of recording, the song is sent to the contest secretariat. Most composers would say that you should not expect anything after the submission because there will be a thousand entries and yours will have a very slight chance of winning.