So I'm not sure why that's not displaying for you. Open up the sessions then fee for the session and check that "display" says yes. Then it should show up automatically on the session selection page on the far right of the banner next to the title and above the description.
It could be that the color assigned to that text is the same as the background or something (it is on the header which is a different color than the background).
But that's really all there should be to it.
Let me know if you need help.