Hi Jorge,
You can get from here TWR-K21D50M Sample Code the sample code for the board, inside the folder that is installed in the next path TWR-K21D50M Sample Code\TWR-K21D50M_SC\build\cw\TWR-K21D50M-OOBE you can find the Out of the Box demo for the board, this is the source code for the demo, you can find the version for IAR IDE also.
I hope this information can help you.
Regards,
Adrian