1. The most effective thing is to drink protein powder, and protein is the most adequate supplement. Of course, it's ok to drink milk when conditions don't permit, but the protein contained in a bag of milk is not enough.

So the most scientific thing is to make a cup of protein powder+a few slices of whole wheat bread before exercise, and then make a cup of protein powder after exercise.

If you have enough money, you can add creatine monohydrate before exercise, in order to provide enough strength for exercise.

2. If you grow muscles, 8- 12 times is enough, and 15 times is a bit too much. It's time to increase your weight.

If the number of groups is more than 5, the number of groups is slightly less. Of course, if you practice a muscle in several movements, you can practice it in three groups, such as upward oblique bench press, horizontal bench press and downward oblique bench press, so you can practice three groups each.

3. If you can move, you can practice according to the video. In fact, there are many tricks. You don't need to practice every one. Find someone you feel comfortable with. In the same way, the rest between groups is 1 minute. After completing an action, you can rest for a few more minutes.