Cut the White wire at 2cm, Green wire at 3cm, Red wire at 4cm and Yellow wire at 5cm length respectively from the edge of the cable.
Then, pre-solder the wire to get it ready to solder to the 3.5mm jack's required 4 apparent spots. Place the jack as trapped between the jaws of the flat pliers securely. You may hold the hands of the pliers simply by rubber band or a peace of nylon or clothes.
Then solder the shortest wire to the finish end of the jack (the thinnest soldering end), which is the White wire. And so on until the Yellow wire being soldered to the wider edge of the jack. Remember, you should solder just a tiny bit, not much, and the best way possible. Do it as much polished way as possible since the iBeats metal exterior is not flexible and has a very limited space. Examine it before soldering closely.