Generally speaking, if you go to school, it will take about two or three months. The school's equipment and training materials are relatively richer. There are many training operations, and it will naturally be easy. Usually you can learn it in two or three months, and then you will accumulate experience.
If you go to a physical store to learn, business is good, and you often study for six months to one year, provided that people are willing to teach you. Physical stores have fewer internship opportunities because of the material receiving restrictions, and more are for you to see.
Of course, whether you study in a physical store or at school, you can really master this technology only by studying hard and practically. You can't fish for three days and dry the net for two days. Only constant persistence, constant consultation and constant practice are the most important.