The normal procedure is to pay the application fee and examination fee after obtaining the patent acceptance notice. There is no need to wait until you obtain the preliminary examination certificate before paying the substantive examination fee. Paying it in advance can greatly shorten the time of the substantive examination. The actual review will take about 18 months, and one or two notices of supplementary opinions will be issued during the process. If everything goes well, the actual review will be completed in 20 months, and the remaining two and a half months will be announced.