UK Car Repair: engine starts,,no keys, starter solenoid, egg run

Question
what is wrong??? metro 1300cc,triked,,replaced starter solenoid as was broke,,went to connect battery,,neg first then positive touched terminal and engine started to turn over without keys in or starter button depressed,,,any help pleez ,,goin mad trying to sort out so can do glasgow yorkhill easter egg run 23rd march,,,,HELP !!!!!!!!!!

Answer
First, when working with a battery, ALWAYS DISCONNECT THE NEGATIVE FIRST & RECONNECT IT LAST! THERE ARE FOUR OR MORE CABLES ON THE SOLENOID & THREE TERMINALS. ONE LARGE TERMINAL HAS A LARGE CABLE FROM THE BATTERY, AND ONE OR MORE SMALLER ONES WHICH GO TO THE VEHICLE FUSE BOX. THE OTHER LARGE TERMINAL HAS ONE LARGE CABLE GOING TO THE STARTER MOTOR. THEN THERE IS A SMALL ONE WHICH COMES FROM THE IGNITION SWITCH TO A SMALL TERMINAL ON THE SOLENOID, THIS IS THE ONE THAT ACTIVATES THE SOLENOID, YOU HAVE THEM MIXED UP!