C7100V- prioritizing devices

so this router is set up and I have ethernet connected from this router to the TP-link powerline. And I have tmobile asus router downstairs connected through the tp link. The problem is that the downstairs is now not getting enough download speed, and this new nighthawk router seems to hog all the mbps. Is there a way to prioritize the deivces connected to this? I've tried going to the netgear genie and going to the advanced setting, but I got stuck there because there were no doS or QoS like the instruction said.