Q.Starting a coral tree from an existing tree
My 9-yr-old has a Project. Start a coral tree for our HOA. Step by step please. We have a bloom floating in water now. Should we cut a branch instead?
We are not gardeners but want to learn

No, you will not be able to propagate with the flower, but i'm sure it's lovely.
This link will help you with the process of propagating this beautiful tree.
https://mindyourdirt.com/2015/08/15/how-to-propagate-a-coastal-coral-tree-erythrina-caffra/
This is not an easy process but what a great project for your child!