"Now i replaced the cables of the CD RW with that of the CD RW( 1 power cable, 1 for the parallel wires, and 1 wire comming frm the mobo)."
i assume u meant u replaced ur CD RW with your DVD RW drive
yes , u need to find two more such free slots to connect your 2nd drive.
both of them go into the respective slots at the drive end.
the other cable u are talking about could be tha audio cable that u connect to the audio port on the MoBo. usually used to listen to music thru the drive.(u need to plug in a headphone into the head phone jack on the drive.
could u post pics so that it can be confirmed.
now, to make it a secondary slave,u need to change the jumper settings.
the exact position should be given at one side of the drive.