Going from the spec page, it looks to include an audio cable so I'm assuming it'll accept a standard 3.5mm audio in from the PC. Basically, just run the included audio cable (or any male-to-male 3.5mm audio cable) from the front line out on your PC to the line in on the monitor.
Now, I have *no* idea if the monitor supports audio over HDMI. Just because HDMI carries audio doesn't mean the monitor will accept the signal. I'm assuming it does, since most monitors that have included speakers also accept audio over HDMI. Otherwise you're going to have to get fancy.