rotor hex bolt is a 6mm allen key.
front caliper carrier bolts are 16mm (5/8 fits too) they need to come off to remove the rotor, the issues with cheap off shore rotors, are that they are inferior metal composition and could wear / warp faster than the oe or a performance one. FYI
leave an the old pad in place over the piston, and use a large C-clamp to carefully and slowly push the pistons back in. also, carefully monitor the brake fluid reservoir to make sure it doesn't over flow etc. use a syringe or something to draw off some of the excess.
as suggested before, this is a good time to bleed off the old brake fluid and add some fresh stuff (with no moisture in it! as moisture is the killer of brake calipers and lines.)
Read the article about the brake change, its good! has the torque specs in it too.
also have a look if you need rear brakes as well?? usually the fronts wear faster than the rears. but if you are in there... also, check the park brake pads under the rotor of the rear, they may be worn also!!