No, that is not the correct code for the from address, that is the code for the Validated Entries binding, which will only have a value if form validation fails.
to use the email address of the person filling in the form, use the binding for the email field from the form collection on the bindings panel, not the validated entries collection.
to edit the universal email settings, go to the Server Behaviors panel (Window -> Server Behaviors) in the list of server behaviors, double click the Universal Email server behavior.