Opera 15+ has no classic bookmarks access/manager. They replaced it with a Speed Dial folders / Stash vision and only after some users' demands they integrated a bookmarks bar and API (further development of this kind of bookmarks is unknown publicly).
To access and manage the bookmarks in the root folder and other folders you'll need and additional extension like Neater Bookmarks (direct download), which will add a button to your toolbar to display them. Enable it in the menu - Extensions.