If it's only 20kg, you can practice squat, but it's still a little light. It is best to have a barbell of 40-50KG, which is the best. Of course, it depends on your personal situation. If you are a girl or just started strength training, you can take your time.

If you want to exercise your muscles, it is recommended to increase your weight. It is ok to practice upper limbs at 20KG, but not much for lower limb muscles. You can practice endurance if you work in multiple groups.