How do I decorate this huge piece we just bought?

How about books, baskets, and some other fun items like something you collect?

I would get some cute baskets at Target (they have a great and inexpensive selection) for the bottom. On the top, you could put some candles with a vase.

Let’s see now: the big fireplace? the big tv? No, the elephant of a table! How about removing the top and the round squat feet. Then, stand it up with the bottom against the wall. Place shelves across the spindles. Sand and stain the shelves and their brackets, or use glass shelves. There should be 4-6 shelves. This will take up 3’ of wall space and 6 sq. ft. of floor space, instead of 36 sq.ft. of floor space. And you will have a unique and attractive piece of furniture to help balance out the huge fireplace and tv. Just an idea, Elizabeth! ☺️

Keep it simple, do not "over clutter" the space with too much to look at.

If you are taking accessories consider symmetry in each side of the tv.

Elizabeth, what kind of decor do you like? That's the place to start. You could even paint your brick white. Put coordinating fabric cubes on the shelf under the tv. You could adapt one for your wires. Let us know which way you want to go with the decor and we'll help.

Just a thought, check to see if the light is producing heat. If it is it will screw up your thermostat. Consider moving it or look below.

The silver tone of your TV is going to throw off anything until you bring something else sliver onto the shelves. A statue, some pictures in silver frames, a plate on a stand anything in your taste. Even some silver fabric or bulky silver book stands. If the wouldn't reflect the back of the TV even some mirrors. Like another poster mentioned it needs to be your taste so it's tough to make recommendations.

Right now, and I know it's brand new to you, the lights look too small with the big TV and heavy shelves. If you don't need the additional light I'd remove them and look for something tall and narrow you could hang on either side of the TV (and cover the holes). Asian scrolls, wood carvings, pictures, bird houses, framed fabric, etc. Just don't add more silver up there unless you have balance it down below.

It's hard to balance a big bookshelf like this when the shelves are short. I have some large, heavy plant books that I would stack, laying down to add weight to the lower shelves but that is me. Look around for something you like that is short enough to fit the shelves but bulky to give the feel of weight. Play with items you have and it may just tweak your imagination.