Log into your site as the admin. Go to the Dashboard, then click the "Pages and Themes" sidebar link. Then click the "Attributes" link at the top. From the dropdown menu at the bottom, choose "checkbox", then click the "Go" button. (See first attached screenshot).

Now type "is_featured" into the "Handle" box, and whatever you want into the "Name" box (I recommend "Is Featured" just to keep it simple). Don't worry about any of the other stuff on that page. Now click the "Add Attribute" button. (See second attached screenshot).

So now the attribute is installed, but you'll need to set it on the pages you want to mark as featured, which you can do when you first create a page by choosing "Is Featured" (or whatever you named the attribute when creating it above) from the "**Add Attribute" dropdown menu underneath the name, date and description of the new page. If it's a page that already exists, go to that page, click "Edit Page" in the toolbar, click "Properties" in the toolbar, then click the "Custom Attributes" tab and choose the "Is Featured" item from the "**Add Attribute" dropdown.

Hope that helps.

-Jordan