No, you only need to update your account. Find the Log In Section in the right column of the landing page. Log in with your username and password. If you have forgotten your username or password, you can reset it.
On the main page you see the note “Berlin Buzzwords 2017: subscribe to event”, click on it and you will be asked "Are you sure you want to join the group Berlin Buzzwords 2017?". Click “Join”. You will return to the main page, click now on "Dashboard" and go to "Add Session" in order to submit your new abstract.