How long does it take for C38 visa to return to China to sign H2?

C38 visa holders aged 25-55 will participate in the computer lucky draw (if the policy remains unchanged this year, there will be four lucky draws), and after winning the prize (almost all applicants will be drawn), they will go to Korea to study for six weeks as scheduled. After studying, they can apply for an H2 visa and have no criminal record.