Action when picker item selected

I am having a lot of trouble figuring out how to trigger an action once a picker item is selected. Anyone have some guidance on this? Thank you

Picker(selection: $myPick, label: Text("")) {
ForEach(0..<mySpan.count) {index in

Solved it by using a list and passing a value to the next view.
NavigationLink(destination: MyMapView(myValue: 1))
Thank you