Dig soil from the area where the post will be installed. The holes should be a bit larger than the post in diameter to allow more space for the jackhammer to chip away at the rock.
Hook up the jackhammer to the appropriate power supply. Inspect the tool for any broken parts or defects prior to using. Make sure the jackhammer is equipped with a pointed-tip bit, which is used for breaking solid surfaces. Next, put on appropriate safety gear such as goggles and steel-toe boots.
Place the tip of the jackhammer into a small groove or pit on the rock that needs to be chipped away. Always hold the jackhammer at a slight angle away from your body to allow for added weight as needed; lean into the jack hammer to apply additional pressure.
Turn on the power by squeezing the jackhammer's trigger or toggle into position. Keep both hands on the machine while you are hammering into the stone. Do not let the jackhammer's bit sink all of the way into the rock, which could make tip removal difficult.
Remove debris from the hole every few minutes or as needed to prevent the work space from becoming cluttered.