Adjusting a caliper brake is pretty straightforward.
First off, loosen up the cable anchor bolt with an allen wrench. Make sure the quick release lever on the caliper is closed and not opened. Next, close the caliper with your hand to right about where you’d like them to be, in terms of distance of the brake pads from the rim.
If your brake pads are not perfectly on the rim and are either angled up or down, loosen the bolt that holds the pads in place. Close the caliper to position.