CC2530: sending message

Part Number: CC2530

hello,

following the previous posts, I passed these steps by now:

1) the coordinator starts the network successfully

2) the end device joins the network successfully

now I want the end device to send a message which contains a string like "Hello World" to coordinator.

what should I do?

I'm using Z-stack 3 , IAR compiler, temperature sensor and thermostat sample apps.

thanks