Staring a Corsa, connecotrs for the solenoid?

when i turn key the battery light etc. come on as normal,but when i go for the final turn to start the engine nothing happens(just a click) Its obvious the solnoid needs attention.
ps. no bother starting with a push or on a hill.

I want to clean the connectors for the solenoid and the battery. I dont know where the solenoid is tho any ideas?