First of all, for the purpose of muscle training, usually at least four exercises are selected for a muscle part, and each exercise is done in at least four groups, and each group reaches exhaustion 8- 12 times. Bench press and flying birds are the main exercises of pectoralis major. If you don't get enough exercise, add it twice.

Secondly, it is considered whether the movements are standardized, because each exercise will exercise to several different parts. If the movements are not standardized, the secondary exercise parts exert too much force, while the muscles in the main parts exert too little force to achieve the exercise effect. No matter what kind of exercise, you should always focus on your target muscle when doing the exercise. In addition, you must always consciously feel the stretching and contraction of the target muscle during the action, so that you can be sure of the action.

I hope I can help you, please adopt it.