It's a 2 step process in TT. Answer yes that you have book expenses to get to a 2nd screen to enter the amounts.
Go through the entire education interview again. It should be the 2nd screen. If you miss it again, keep going until you reach a screen titled "Your Education Expenses Summary". Click edit next to the student's name. That should take you to a screen “Here’s your Education Summary”. Click edit next to "Other Education Expenses (for all schools)".