Remember this:
When operating a solenoid, there is going to be the "switch" side and the starter side.
The larger posts or screws are for the larger wire, or starter.
So you should have a wire from battery to solenoid, then from solenoid to starter.
On the two larger screws...
On the switch side, should be your starter button, or whatever you are using.
That should be a smaller guage wire than the battery because you arent using as much current.
I hope I am explaining this well enough.
You need power to operate the solenoid.
Which would be the switch side. Or starter button, whatever you want to call it.
One wire from the battery to a button to the smaller screws on the solenoid.
This will energize the coil in the solenoid, closing the circuit for the starter.
You can test it without the starter wires connected just to be safe at first.
When you apply 12v to the switch side, the solenoid should click....meaning its working.
Do that first, and secure it, because it might jump a hair...lol
Once you've established that the solenoid is working, you and connect your larger wires.
Remember, you are drawing a lot of current to operate that starter.
So you need a larger guage wire...typically the same size as stock or I use 6 guage...8 guage works too...
Hopefully this advice helps ya, any more questions...shoot me a message.