When someone comments on something of yours (such as a piece of artwork or a group discussion or a comment you've made somewhere) you'll get a notification.
You'll see these notifications at the very top of the site (the notifications icon looks like a bell).
Clicking on the notifications icon shows you a list of new notifications you have. Clicking on any of those notifications takes you to the page and place where the comment was made.
How do I see past notifications?
Once you visit a comment you've been notified about, the notification will disappear from the bell icon.
You can see past notifications by going to My Notifications from the My ArtTutor menu. This will show a short list of notifications that you have already viewed.