Hi Evan,
Yes, learning how build a custom PC can take some time, if not years, so I feel your pain. That PC is alright but overpriced and not what you want for trading. A gaming PC is not a Trading PC, not by a long shot. That CPU is vastly overkill for trading, more towards gaming, so you're paying for something you do not need and won't use. The GHZ doesn't matter much anymore like it did in the 90s and 2000s, it's all chip architecture now just fyi.
My professional advice is...grab this PC and video card below. It's cheap and powerful and all you need for a number of years to come.
I did a scan of Newegg (the best overall online pc hardware site) and I say buy yourself 1 key component, a graphics card that can run 4 displays well, and not a lower-end gamer card (in the PC you selected) that can hybrid into multi displays, barely. The Nvidia Quaddro driver support will be much better and stable for multi display in Windows.
https://www.newegg.com/acer-aspire-tc-885-student-home-office/p/1VK-0017-00AY9?Item=9SIAEYA96C6574
https://www.newegg.com/p/1FT-0014-00118?Item=9SIA6ZP7EZ3426&Description=nvidia quaddro p620&cm_re=nvidia_quaddro_p620-_-1FT-0014-00118-_-Product
Let me know if you have any questions, installing the gfx card is extremely easy, you just drop it in like a memory card and install. I would be happy to help!