Easy, lame, and unreliable way to water cool your PC is to use an AIO solely for your CPU.
There isn't much way you can get the water block itself wrong. As long as you get the LGA 1151 model, you can get it in any color you want, acetyl (plastic), nickel, and then one other option for color. As for the GPU, make sure to match the GPU's custom cooler. Some GPUs will have water cooling included; those costs more but you may not need to Buy a reservoir (must have high volume) and pump combo, and a radiator. Then, you'll need a radiator; 240mm recommended. After that, all you'll need is bearings (just make sure the size fits all your water cooling gear) and for tubing, I recommend soft tubing because it's much less of a hassle and much...