Fade help

[Cristisor]

Hi. I didn't work with MooTools before and now I need to make a fade
in for 2-3 seconds and then a fade out for another 2-3. I tried
    var myFunction = function(){
        var div = $('hiddenDiv').setStyles({
                display:'block',
                opacity: 0
        });
        new Fx.Style(div, 'opacity', {duration: 1000} ).start(1);
    };

    myFunction(); //<- this does it all

but I always get the message: Fx.Style is not a constructor. I
downloaded the latest mootools and included everything, including
Effects, but it won't work. And can anyone tell me how I could delay
the next execution, something like afterFinish in Scriptaculous? Thank
you!