Waiting list for Mine Clearance

Hello, so today I was told my application would be approved to go further in regards to the mine clearance role after having passed my follow up interview. I was told the waiting list is 15 months however, I have no clue as to when the timer for this starts. will I be completing my PRNC first? or will I be waiting 15 months before I can start any of the process. In hindsight I should have questioned it on the call!