Lower part of pectoral muscle: Lie on your back (head down) at about -30 degrees, and push the dumbbell (barbell) vertically upward to the ground.
A variety of instruments, depending on your current ability. Each group can do 10- 15, and it is enough to do 4 groups at a time.
If there is no inclined board, you can lean on the sofa or chair to find your own angle. When you feel almost done, start to do muscle exercise according to the above requirements. Of course, it's definitely not as comfortable as leaning on the inclined plate. Exercising muscles in different parts is faster than the whole exercise. Remember one thing, where you feel hard and sour, that is, where your muscles have been exercised. I wish you more and more style.