A variable is a constraint that a user selects when the query is processed.
To use all selected members as a variable (the user is prompted for the values when the query is processed):
In the data layout, right-click a dimension member and select Edit.
Select Use as variable.
Click OK.
You can also a member in the data layout and on the shortcut menu, select Variable.
To use all selected members as a variable (the user is prompted for the values when the query is processed):