Even before you start working with an actual piece of hardware, you need to design all the logic first, in addition you need to code all the functions and procedures that will be responsible for making the processor work. act as intended.
YouTuber AstroSam decided to accomplish exactly this feat by building an emulator for his own 16-bit processor. Currently, only the emulated version of this CPU has been tested. As the author said, developing an actual piece of hardware ‘could take a few more years’. Watch the following video explaining the basic steps required to complete the initial design of his own CPU: