Please have a look at these video tutorials on the use and procedures of using Marine VHF DSC Radios.
Setting up a Marine VHF/DSC Radio.
Individual calling using Marine VHF DSC Radios.
Distress procedure via DSC Radio.
Urgency PAN PAN Broadcast (DSC)
Urgency Alert Mayday Relay Broadcast (DSC)
How to Access the web-based Online RYA VHF Radio Course