Hi, first timer here looking to build a gaming PC out of separately bought parts for the total price of about 750$ at a maximum. Need help with specifications and parts information, please.

I'm entirely new to this, and I'd heavily appreciate it if somebody could recommend parts that will have a total of roughly $700-$750 dollars. I have a monitor, mouse, and keyboard of my own I can use, so the tower is all I need help with. I was looking at this earlier, but I was told I could assemble one much better for the same price.

EDIT: Any help would be appreciated, because I don't understand how one (for example) GPU is better than another just by reading the title, etc.