When you push your chest, 100% of the triceps will exert force. The reason why I feel that my triceps are sore and my pectoral muscles are not sore after training is because my pectoral muscles are not well trained, because my triceps strength is far less than my pectoral muscles. When you push up the equipment, your triceps are weak, which limits the weight you push up. The other line is that your shoulders bear a lot of weight. But stick to it for a while, and the pectoral muscles will gradually become bigger. You should also pay special attention to distributing the exhaustion on your shoulders to your chest as much as possible.
Now I'll tell you how to stimulate your chest. Don't care where you are strong during training, because when you push your chest, almost all of you will be strong, especially when you push heavy objects. In fact, your toes may also be exerting force, not to mention large muscle groups such as arms and shoulders. When you push your chest, your subconscious mind and attention must be focused on your chest, just thinking about your chest.
Next, we should pay attention to transfer part of the force borne by the shoulders and triceps to the chest. Specifically, the shoulder sinks down, the elbow is a little lower than the position parallel to the shoulder, and then the elbow should be retracted a little (this can reduce the stress on the triceps brachii). Then your chest exerts force to drive the whole shoulder and arm movement. Remember to push the chest first, and then drive other parts. This is possible.
If you still don't understand or don't understand, I suggest you widen the scope when you practice your chest, so that you will definitely practice your chest. Usually, you can also think about how the chest drives the unarmed force, and the adjustment of the elbow and shoulder position is the key point.
If you are overweight, you have to exercise all over. Do aerobic exercise properly and spend more time on foot. When you go to the gym, you should run on the treadmill. During equipment training, the rest time of each group should not be too long In the early stage of fat reduction, it is best to do several parts together. Try not to let yourself rest too much. The weight of the equipment does not need to be too heavy. If each group can achieve more than 10~ 15, practice as many groups as you can in 30~45 minutes anyway. I guess you've just started working out for a few days. Do all kinds of instruments and bench presses as much as possible so that you can exercise all your muscles first. This is from experience.