For the sync to work you need to login with the same login details that you have for the Link service as for teh new service!
I found that the New(er) Opera browser sometimes does not keep me logged in.
Once logged in I found all my pages in the Bookmarks section under imported Bookmarks (including all my other devices start pages as well as the synced bookmarks.) What did not carry over, and I have a feeling there is no way doing it: The Notes from the bookmarks since there is no place for them to go into the new Bookmarks...
Also the normal Notes (not from the Bookmarks) are not synced any more. And I have found no way (yet) to keep them unless I keep an old version of Opera installed.
For the Bookmark notes I found the solution of exporting all my Bookmarks as HTML.
Place the HTML file somewhere safe.
Open it an create a New Bookmark to this Bookmark HTMKL file.
When opening it you can use the normal page search function to find you notes or simply scroll down to read the notes (which can be a long way down... I have close to 6000 Bookmarks with a lot of nesting)
