How to change the ISO

Changing the ISO is only a patch for the problem - although it will allow you to take pictures with a faster shutter speed (which will help with motion blur) it's not panacea - it will add significant noise to the photo

I'd advise instead on of the following:
1) Place the camera on a tripod or other sturdy surface (like a desk)
2) Use more light (or, better still, use the flash if your subject is close)
3) Use the self-timer - a lot of camera shake originates from the movement of the finger on the shutter button

If you still want to change the ISO, check the camera manual (not all cameras allow you to change the ISO)