Melina's note on the office door asks you to make sure the vase exhibit is properly labeled. You need two things: a book about Greek art, and the loose labels. The book you can get from the Hardy boys.
Once you have the labels (which are in the right drawer of the filing cabinet), go look at the vase display in the museum (there are two groups of vases, and you want the vases on the right), and Nancy will pop up the labels for you to put in place. Read to the end of this hint to find out which label goes where.
The book is not nearly as much help as it might be, because it doesn't have pictures; it only has descriptions, and some of them are pretty vague. The oinochoe, for example, is "a single high-handled vessel, taller than it was wide, with a trefoil mouth ... used for serving wine." Hmm. Not too helpful, when we can't really see the shape of the vases' mouths.
If you look at the vases, there are two tall pitchers with one handle and a top that isn't exactly round, the middle top and the lower right. The main difference is that the top one has a pronounced lip. Could that be a "trefoil mouth"?
For some of these, you'll have to use a process of elimination. There's only one that's "a small circular box with a lid," so that one must be the pyxis, and there's only one with no handles and no foot, so that's the lebes.
When you get them all right, Nancy will say, "That's it!" If she says nothing, it's back to the drawing board.
If you're impossibly stuck on this, here's the correct layout: