If you mean the "Dock"-like icon bar, it's called a "Panel" in Ambient. So go to Ambient Settings, select "Panels" click on "New Panel". A small gray area with an arrow icon will appear, which is the collapse gadget for your new panel. Otherwise it will be empty.
You can then either edit the Panel from the Settings window there, or by right clicking on it, and use the context menus, and by drag & drop.
Thanks for reminding me.