Newbie question regarding initial hardware setup

So I installed Cubase 9 and am excited to begin recording my original songs. Have a new pc with Win10, Intel i7 and 32 gb ram. I built my first home recording studio with a Yamaha MG12XU mixer, a pair of KRK Rokit 5 Gen 3 monitors, Sennhieser HD 280 Pro headphones, and two Shure SM57 mics for micing my guitar amp and drum amp. Connected all components with xlr cable, and from the mixer to my pc via usb 2.0 cable. Everything is working great. I also installed the latest ‘Yamaha Steinberg usb driver V1.9 10-2 for win 10/8.1/7(sp1)(32bit/64bit)’. My question is, I want to playback my Cubase tracks/recordings only through my KRK monitors (which are connected to the mixer). In other words, I do not want to listen through my pc speakers. Can I bypass my pc sound card when using Cubase, or do I still need to connect my KRK’s directly to my sound card, which I’m assuming would require me buying a usb audio interface such as the UAD Apollo, which seems unnecessary since I have the mixer. Any ideas greatly appreciated, thanks!

Bill

Yes connect your speakers to the Yamaha and use it as a soundcard.
In Device Setup under VST Audio System/ASIO Driver you choose your Yamaha USB driver.
And under VST Connections (F4) you set up your IN’s and OUT’s
I expect the yamaha having 2 ins and 2 outs via USB, that is normally the case with these kind of mixers.