Here's the link to the Virtual Developer Day to be held in the EMEA region today:
If you use the old link, to the Virtual Developer Day in the Americas, you can watch all the sessions, but you won't get the live chats with the speakers, etc. Best to use the above link if you're attending today.
You'll see once logged in, which can be done from when the Virtual Developer Day starts, that the sessions are timeboxed, so that you first need to watch the keynote, then sessions per track in a specific order. All the sessions build up a complete picture of a particular technology, Java SE, EE, or Embedded, and it pays off to watch all the sessions in a particular track.