urgent need help on wiring a car radio.

how do i wire this... from back of car there is two wires one red( sure this is live) one black not sure what this is????? from radio, 4 speaker wires 2 are + 2 are - i think u wire all to speakers, one red wire which is live and one red and yellow wire which i think is also live.... one brown wire by the name of ground what is this wire? i want to wire 2 front speakers also.... hope u can help...... i tried the above red to both lives speaker wire used all 4 , for 2 speakers, and put the ground to the black wire,,,,, not sure if i should of done this streo worked ok but i got little electric shocks of radio, what do i do now?