1. Go to Layout -> open the "Slider" widget.
2. Replace this part of the code:
<script type="text/javascript" src="/feeds/posts/default/?published&alt=json-in-script&callback=autoslide"></script>
3. With this: <script type="text/javascript" src="/feeds/posts/default/-/Featured?published&alt=json-in-script&callback=autoslide"></script>
4. Change the word Featured that's selected in the screenshot below with the label you want to display posts from:5. Click on "Save".
Here's the code for the slider, in case it's deleted:
<script type="text/javascript">
var numposts = 4;
var displaymore = false;
var showpostdate = true;
var showpostsummary = false;
var numchars = 1;
</script>
<script type="text/javascript" src="/feeds/posts/default/?published&alt=json-in-script&callback=autoslide"></script>