Good day everybody 😌😁

I come asking for advice as I am a noob in engine wiring with a simple set of instructions I know I can't go wrong... My only problem is I am very cautious.
I building an e30 with a m50 motor(OBD1). My dilemma is the engine to body harness plug was cut off of the harness when I bought the engine Now I've searched for a plug but I can't find anything so I chose to connect the wires necessary and insulate them with electrical insulation tape.
My first question is
*the terminal 30 from the starter which is grounded to relays k5 & k7 (unloader relays). My problem is the wire is bare and I don't know how to actually connect it (such as to ground it to these 2 relays ) please could someone direct me and tell me how exactly to do this
I'm prepping for my first start and I just want to be 190% sure I'm covered in wiring.

* secondly my airflow meter plug has a red and white wire which is also cut and bare on the engine to body connector I know this is the wire for the airflow meter (I connected my multimeter and did a continuity test and it was the same wire... Please help as to where does this wire connect to (I have assumed this is a switched power which provides current from the battery as to operate the airflow(I could be wrong) but as to where to connect it I'm very lost 😩😩😩&#128553)

* thirdly engine temp sensor I've opted to drill and regal my jeans to fit the single pin brown top coolant sensor. To give my cluster a reading does this wire connect to? From reading on the internet there's already a wire I need to splice and join and I've done this but I'm left clueless as to how to connect this coolant sensor for the instrument panel should I run a secondary wire. And connect it to a certain pin just for the cluster or what ...? I figured since there's only 1 plug on my harnes for engine coolant temp I figured this one I've connected is for the ECU

My body harness connector is the old rectangular c101 so. I only had about 12 wires to work leaving me with more unconnected wires (from engine harness) than connected which creates a cause for concern with me


please help as I'm very keen for my first start and drive It is urgent. As I have a deadline I'm trying to meet ❤️
many thanks guys