In order to create your own commands, you must select a name for it which doesn't exist already in the system. Then you must include its name, description and parameters in the commands static table.
const COMMAND commandTable =
And now, you must to implement the cmdPlay function to perform the action you want.
ERROR_CODE cmdPlay(TERMINAL* pTerminal, INT num_args, STRING args)
The parameters are passed to the command using the array of strings "args" and the number of arguments in the array in "num_args". You can use TerminalPrintf and other available API functions in order to send the response to the user.