Building my Rig, But IDK what i'm doing , Need help .

So i been at this for a few hours now , i'm watching plenty of videos trying to do this, i tried the video suggested on the home page to the right.It's just so different between using a phanteks enthoo evolv, a modular power supply, ssd, hdd, and a z270 motherboard.

i've connected my powersupply, the motherboard to the chasis , the memory, the water cooler , the hdd