NC Child is a nonprofit organization that educates parents of young children with I/DD. But it has materials of use to older parents too, such as their webinar on advocacy.
To see their archived webinars and what’s coming up, visit: https://ncchild.org/what-we-do/upcoming/
Scan down the page. The advocacy webinar they did on February 25, 2022, can be seen as slides or as a recording. It’s also available in Spanish.