Bought a install kit for my 2002 chevy blazer ls and I can't figure out how to get it to assemble. I was told my oem radio is a din and 1/2 and this kit fits 1999-2003 models. The guy at metra was a jerk and said all I need is the actual mount no side brackets but I tried to install it and its too narrow but I don't see how the brackets would fit on the mount as there are no screw holes. Any help is appteciated