Once you have the installer from driver4vr.com :
I strapped a phone to my ankle, fired up Driver4VR, and suddenly my VRChat avatar wasn't a floating torso anymore. It actually has legs. Kinematic legs. Do they occasionally glitch out and make me look like a baby deer learning to walk? Sure. But for the price of zero dollars, it is genuinely impressive technology.
: This is the safest way to ensure the software is "verified" and free of viruses. Test your Hardware