Using RTC to Put BLE Device to Sleep for Hours

Device PSoC4 CYBLE-224116-01

Hello,

I am trying to create an application where the user can put the BLE device to sleep for certain hours.

I have created a service which has two characteristics; 1. Sleep time and 2. SleepNowFlag.

The user enters the duration for which it wants the BLE device to sleep, and they write on to the SleepNowFlag when they want to put the BLE  to sleep.

The firmware in the BLE device keeps checking the flag; and when the flag is set it puts itself to sleep.

Now i want the device to wakeup when the sleep time is over and start advertising. I thought of using the RTC Alarm Feature but am not able to figure out how.

Please Help!