2.0l EFI pinto turbo conversion

Hi after abit of advice. So I’m building a pinto turbo for my 1990 sierra sapphire it has a 2.0 8v dohc in it. So I have everything to make it fit match gearbox etc….  So I’ve  decided to run a early 2wd cosworth L1 ecu and harness modified to fit the pinto efi using the cosworth throttle body and sensors along with ign module and map sensor i also have a pinto chip to install into the cosworth ecu. So! The part I’m struggling with is… where does the wiring from my sierra ie dash warnings ign feeds join the cosworth harness as I can only see the basic plugs connectors for injectors tps air temp water temp ign module crank sensor, icv valve coil. I don’t have anything for the alternator or starter on the cosworth harness?? Am I missing a harness or can the one from my sierra be used? Or any advice on where to obtain wiring diagrams for both the 2wd cosworth and the sierra Glsi? Any help is greatly appreciated many thanks!!