If you're looking for resources to help you improve your composition skills, there are many great books, online courses, and music theory resources available. And don't forget to listen to the works of other composers for inspiration and to gain a deeper understanding of the art form.
You could start by teaching them about melody and harmony and then move on to more advanced topics like form and structure.
To help kids learn about composition, encourage them to create melodies or write songs. You could also try playing games where you give them a few notes and ask them to build a melody around them.