The only connections needed are the main live from the battery to the 13mm terminal on the solenoid, furthest from the actual starter motor itself, then opposite this there is another 13mm nut/terminal that has a tiny length of braided/covered wire that goes into the starter motor body.
Placing a 50 pence piece across these two will make the starter motor spin, but NOT turn the engine, as it is not engaged into the flywheel teeth, I'll explain.
There should be another wire, sometimes a round connector, sometimes a spade connector, when this one is fed with a LIVE(through ignition switch) the solenoid(the bit that the cables go on) moves a piston assembly inside, this engages the starter motor teeth with the flywheel teeth, just before travelling a few mm more and bridging the two large 13mm nut terminals inside the solenoid housing and causing the electric to flow through to the starter motor itself and so turn the engine.
tabetha