It's easy! Simply press the green button once you have highlighted the channel you want to lock on the TV guide and then enter your Play TV PIN. A lock icon appear next to the channel name indicating that the channel has been locked.
To unlock simply highlight the channel that is locked on the TV guide - you will see a lock icon next to the channel name - and then press the green button on your Digicel Play remote followed by your Play TV PIN. The lock icon will disappear indicating that the channel is now unlocked.