Hi SteveK
There's a lot of potential variables in dashboards in terms of complexity e.g. number of embedded dashboard layers, nested parameters, etc. But, the best rule of thumb for using Supplied Parameters is if you are receiving a parameter prompt from the target (receiving) dashboard that contains the component or components that you are trying to pass the parameter value into, then you need a Supplied Parameter component in the dashboard that is causing the parameter prompt dialog window to appear.
This is their purpose e.g. to facilitate parameter handshakes. So the dashboard invoking a parameter prompt is the one you want to target based on your setup, refresh actions, etc
Supplied Parameter
Hope this helps
Sam