Once you have shared a canvas, you can collaborate on it in real-time with other users. When multiple users are using a canvas, you will see everyone's icon in the top right, along with their cursors in the canvas.
If a user has View permissions, they will be able to view the canvas but not change anything. If they have Edit permissions, they will be able to freely edit the canvas.
When collaborating with other users, it may be helpful to follow their movements and actions. You can do this by using the lock-on mode. To enter into this mode, you click on a users collaborator icon. When you have entered lock-on mode, you will see an outline indicating your are following someone.
Another feature helpful for collaboration is the live mode. This mode will create a video bubble at your cursor, and will allow you to see and talk to the canvas collaborators in real time. To enter live mode, you can click the go live button in the top right menu.