In a new App, the variable was defined as:
Set(varName, Dropdown.Selected);
in the OnChange properties of a new Dropdown box with DropDownSample in the items.
The Named Formula was defined as:
NamedFormula = varName.Value;
After that, check the Variables in the App by either:
View > Variables (in legacy ribbon)
OR
... > Variables (in modern command bar)
The App would then display a pop up:
Clicking the close button would then proceed to close the App and send the user back to the Apps List
(Power Apps | Apps)
The full details are in the Word Document file attached below.
