Only event attendees can attend the live sessions. You only need to go to the session and enjoy streaming, interact with session speakers through the Session feed, Questions tab, and Polls.
To attend the live session:
Choose the session you want to watch from the agenda.
Or go to the live tab on the left menu, you can see what sessions are live now and the list of upcoming sessions
Click on the session you want to attend and wait for the speaker to start the broadcasting
Now grab your coffee and enjoy the session.
Don't forget to interact with the speaker in Session chat, post any questions you have in the Question tab, and answers speakers polls from the polls tab
To browse the event and still join the session you can use the "Picture in Picture" "Coming Soon"