The starter is bolted to the gearbox and the solenoid (black smaller diameter part on top) is bolted to the starter. Not sure how you'd remove the starter without the solenoid but good effort if you did.
You are best to download the wiring diagram for the 1993 SW20. I can take some phone screen shots of it for the pages you need to look at however I'll do my best to describe how it works and what power should go where.
You need to connect ground/negative to the starter housing. Best place would be one of the two large bolt holes holding it to the gearbox.
12V gets connected to the stud.
To activate the starter you need to apply a wire from the spade connector to the stud you connected 12V to. Be very careful as the starter has a lot of torque so will move a lot when you do this. Clamp it down to something. Also the small gear will pop out the end and spin if everything is working properly. Don't put your hand in front of it.
I did a lot of things that were very much unnecessary, after a few hours I managed to get the starter motor attached back to the solenoid and body, unfortunately I crossed threaded a screw for the brush holder so I will have to also add that to the list of things to do.
I believe everything is ready to test (going off your comments and the BGB) but I don't have a clamp and was hoping to just quickly test it on the ground. Is this a bad idea?
Can't thank you enough for your help!!! Below are some photos of my dirty engine bay and progress (or lack of) thus far.
this is what I was left with after my mistakes
What is this for circled in red? Does it need to be blocked off?
I believe the red wire is the ground from the engine to chassis, this is where I think it joins up to chassis - underneath the air box. I spent some time cleaning this up with sandpaper. I have also sanded down the dirt and bubbling off the paint, do I need to protect the paint with something before putting grounding cables back on?
You can't quite see it but this is where the red wire/ground leads to in the engine bay