The decline cable press is an excellent exercise to target the lower part of your chest. You will need access to a cable machine. Here are the steps:
Set a bench to a decline position (approximately 15-30 degrees) and place it between two cable machines.
Attach the handles to the low pulley on each side of the cable machine.
Lie down on the decline bench with your head lower than your legs, and grab the handles with an overhand grip, palms facing down. Position your hands at chest level with your elbows bent.
Press the handles upward and inward until your arms are fully extended and the handles meet above your chest.
Pause briefly at the top of the movement, squeezing your chest muscles.
Slowly lower the handles back to the starting position, keeping your elbows slightly bent and maintaining tension in your chest.