The Austrian embassy requires that the birth certificate be double-content. What is double-content?

that is, the birth certificate is double-certified. First, the birth certificate is sent to the foreign affairs office of the province where it is located for diplomatic certification and stamped with the seal and seal of the Ministry of Foreign Affairs, and then it is sent to the Austrian embassy for Austrian consular certification and stamped with the Austrian consular seal, so that the double certification can be completed. Generally, I need to go through the above procedures.