Matlab-GUIDE(pop-up menu

[Schahan]

Hello.

function Sinus_pushbutton1_Callback(hObject, eventdata, handles)
% hObject handle to Sinus_pushbutton1 (see GCBO)
% eventdata reserved - to be defined in a future version of MATLAB
% handles structure with handles and user data (see GUIDATA)

x=-5:0.02:5;
y=A*sin(2*pi*x*f);
plot(x,y);

how can i get the Value for A and f from a pop-up Menu.

thanks Shahan.