1. Remove the screw from the frame (skip this if you have a plastic frame version keyboard).

2. Pull off the keycaps and remove the screw on the PCB as shown in following image.

 

3. Take out the side frames.

4. Then you will be able to take out the PCB. 

(Note: Please be careful of the toggles on the side when you disassemble the keyboard and reassemble it.)

FYI: If there is no problem with the keyboard, it is not recommended to try this at home as it can risk injuries and keyboard damage caused by the disassembling. Disassembling the K2 will invalidate the returns and exchanges guarantee.