Congrats on getting a Z and welcome to the group. There is probably more that one thing that needs to be done in order to start the engine and keep it running. You can download the FSM and a beautiful color wiring diagram to really help. As far as the electrical portion goes, there are a few very knowledgeable electrical guys here ( I'm not one of them), but what anybody who is bringing a old car back to life has to do is, go through and clean and check E V E R Y Single electrical connection. That means the dash harness, the EFI harness, the cabin harness and the engine bay harness along with everything that is attached to them. 40+ year old wiring oxidizes, rusts and corrodes with time and moisture. DeOxit electrical cleaner seems to be recommended often. If you do this in the beginning it will help you solve a lot of issues down the road. It's time consuming but well worth it in the long run IMO.
Edit to say that previous owners have often hacked the wiring. Those are always fun to discover and correct?