If you practice muscle explosive force, you should do 10-20, and the weight of each group is 10KG- 15KG.
To exercise muscle endurance, do 20-30 1-2 groups at a time, weighing 7.5KG- 12.5KG.
In fact, after muscle training is developed, explosive power and endurance will naturally increase. When your muscles reach a certain strength (I feel that the current weight has adapted), you can increase the weight of 1.3-2.5KG. When doing dumbbell exercises, don't do it too many times, but do it in moderation.
Personal suggestion (it is best to practice chest muscles and do ten groups of parallel bars every day for three weeks, and the effect is obvious. It is better to practice shoulder muscles and biceps femoris. The best way to practice abdominal muscles is to do sit-ups, 50 times a day, preferably before going to bed. I hope my answer is helpful to you.