tntsmom, are you talking about decorations as are seen in modern Christmas? Or are you talking about the old genuine Ukainian style for Sviata Vecheria
? For information about the old traditions check this link. Ukraine and Ukrainian Christmas at BRAMA
Otherwise, Christmas decorations now follow the European norm - things that we know on this continent. Christmas trees with decorations, etc. If you are going to prepare Sviata Vecheria try the old form - meatless with twelve dishes. Fish aren't meat for reasons I have never understood.
Like Charlie D, I'm wondering what type of food your Aunt served. And yes, Charlie D can indeed talk food!! By your use of the word "fantastic" I'm guessing the meal was a fusion of cusines and cultures. Meatless borshch you must have, and mushroon soup with mushroom filled little ears. Varenyky are necessary - two different fillings I would think. Kasha is so traditional you gotta have it to start the meal. Fish? I hope you like fish - your choice of type and preparation. Two different kinds are very appropriate. My my, I'm making myself hungry.
For "decoration" the Kolach in the center of the table. The link will tell you about it. Time now to start practice if you haven't made yeast bread. The Kolach isn't eaten but it is a vital part. This is a Christian celebration, very old in the land and somewhat serious. The old traditions are being lost in the cities, but in rural western Ukraine, different matter.
Let us know how it goes!! Best to you.