starter motor wiring up correct?

[Sterling]

my starter motor is the bosch pre engaged.... ive ordered it and it shoudl arrive soon, now

the big contact on the solenoid obviously goes to the big red wire.

there are 2 other wires, one is to engage the solenoid, the other does nothing i can see.

i was told to run one of those to the negative side of the coil, and what about the solenoid engagment wire, can that just be connected to the big red lead?

(using a jumper cable and a battery, i tested them, touch wire on the right to POSITIVE and main contact to POSITIVE while a ground is connected, the starter motor engages and spins up, when i connect to the other wire (as far as i can remember) did nothing...)

and help or opinions??