Plug the auxiliary input into the back of the DVD player. The auxiliary input and DVD player should both be color-coded. The red auxiliary cord plugs into the corresponding red hole on the DVD player, the white cord plugs into the white hole and the yellow cord plugs into the yellow hole.
Connect the DVD player to the TV monitor by plugging the other ends of the auxiliary input into the front or back of your TV monitor (depending upon where your TV monitor's auxiliary input is---some TVs feature them on the front of the monitor and some on the back). Plug the auxiliary input cords into the TV in the same manner as you did the DVD player, by color.
Insert a karaoke CD into the DVD player, turn on the TV monitor and press play to play the CD on the TV monitor.