You can go to Xida Business School or School of Continuing Education. It should be held during the summer vacation. I suggest you take a training course. Although online schools are affordable and convenient, sometimes they can't solve many practical problems without giving lectures face to face. Moreover, the training class will also give you exercises in various chapters, and the effect will be better. In fact, colleges and universities have vocational skills training centers, and customs declarers will also have training.