Hang the chain so they are touching the sleeve of the bar. Perform a normal bench press motion.
The difference in this movement is you obviously have to stabilize more but it will also force you to press the bar in a straight line. Pressing in a straight line over your upper stomach will save your shoulders over time. A lot of people throw the bar back toward their face while they press. This movement helps correct that because if you throw it back the momentum of the swinging chains pulls the bar to a bad spot and will cause you to miss the lift. -
This is a good max effort lift or supplemental movement.