The styled bookmark feature allows you to have bookmarks that resemble rectangular tabs, instead of the rounded look. You will first set the style type in Design Template, so the bookmark style will be the same for every edition you upload under that template.

To utilize these style choices, go to Design Template-->General Appearance.

Scroll to the bottom of the General Appearance list.

From the drop down menu, at the bottom, you will see bookmark style. Click here to select Pop Over or Tab Style.

Press Save. 

Now when you add your bookmarks, they will either be squared tabs or a pop over style.

Tab Style looks like this on hover:

As you can see, the tab pulls out so you can read where it is directing you.

Pop over looks like this:

When you hover over it, the bookmark doesn't move, but the label pops over the edition to direct you.

Users must hover their mouse over the bookmark either way to read the labels, whether you select pop up style or tab style.