(Super NOOB question) How I can I make a PCB to the most secure way?

sorry for this question, but, I already collect all the needed parts for make a Zynthian Box V2, but I still stuck with the all-in-one PCB elaboration, I have tried the Iron method for make the PCB, I even bought the Ferric Acid for the PCB, but I cant get that the design gets in the copper sheet, someone can give an idea of how to make the PCB of the ALL IN ONE module?

Thanks in advance

Why do you want that? It won’t be cheaper than ordering one from @jofemodo.
There are online services. But you need to order more than one, iirc.

Because I live in Mexico, a country with a corrupt aduana officers and bad messagery enterprises, for example?

that is the reason that I dont order nothing from internet