Hi Nicole,
You are not seems using a block element - page hero
which includes Posts
in its location to display the title, you should be able to find it at appearance > elements.
Do you want to add the content to all the posts or only one post?
If it’s in the 1st case, you can just add the content below the title in to that Container
block of the element:
https://www.screencast.com/t/xEl9nkStMJuS
If not, then you can create a new block element, add the content, set hook
as element type, set generate_inside_site_container
as hook name, choose location
according to your need.
Let me know if you need further assistance 🙂