What is the order of 4-layer buried blind hole plates?

The 4-layer buried blind hole plate is 6 steps. According to the relevant public information, there are four kinds of punching methods for the four-layer buried orifice plate, namely, blind holes can be punched in the first to second layers, blind holes can be punched in the second to third layers, blind holes can be punched in the third to fourth layers, and holes can be punched in the first, second, third and fourth layers, which greatly increases the operability when we draw PCB. The four-layer buried orifice plate is six-step.