When you start a presentation, others can follow you. The followers' cursor moves with your cursor and their screen is scrolled to the card you select on your map. When you open a card's details, it will be also opened on the followers' screen.
Where can I find it?
Click on the ‘online users’ icon in the bottom right corner
Hit the ‘start presentation’ button
You can stop the presentation by clicking the ‘stop presentation’ button
Don't forget to ask your teammates to start following you.
What can I use it for?
present user journey on the top-level cards
discuss backlog items one-by-one
remote sprint planning