Welcome to TRS
Assuming 1984 electrics
If its a conversion then what year is most of the electrics?
Starter Relay(solenoid) on inner fender has 2 larger posts , and 1 or 2 smaller posts
1 larger post, does not matter which one at this time, will have Battery Positive cable hooked up, AND several other smaller wires, that send out the 12v to other systems
OTHER larger post has JUST ONE cable connected, to starter motor, just one cable on this post!!!!!
The smaller [post(s) WILL have labels, an "S" and an "I"
"S" post has a wire that runs inside the cab, when this wire has 12v from ignition switch turned to START it will activate the Starter Relay, which will then CONNECT the two larger posts together and starter motor will activate