I just looked at mine the other day. You can see them from the rear of the quad. From what I remember they were under under a plastic shroud. Just find the rotor and you'll find the brake pads. Should be something you can take apart without a manual but there is a free download of the manual on the forums here. Do a search for service manual or something along those lines.
I tried this as per manual by loosening the 12 mm bolt on the bottom right of the caliper but couldn't get the pads out so removed the caliper completely by removing the 2 allen key bolts on the left side of the caliper. These buggers were tight and the caliper comes out forwards under the frame rail and drop threw bottom of frame. If you havea rear skidplate you would have to remove this first. The pipe is long enough to drop down threw the lower frame rails and there is plenty of room to check ,change or clean caliper and pads. Only takes about 10 mins to do all that and fit back. Apply medium strength loctite to 2 allen key bolts on rebuild.