cd player wont work 6000 rds?

i have bought a s/hand 6000 rds with cd, the radio works great but the cd does not, when you put in a cd the radio does not switch auto. to the cd player and it makes a ckicking sound like its looking for the tracks and then it spits the cd out and goes back to the radio. also do i have to connect up all three blocks on the back of the set. if not which ones, please help its doing my head in. thanks macca