They first have to state what the offence is. Form 21, the warrant of committal, sets this out as well. It's attached to the bill to make it clear to judges how this will work.
So you state the offence, the amount of time a person has spent in pretrial custody, the sentence the judge feels would have been imposed had the person not been in pretrial custody--that's the particular thing we want to get out--and the amount of credit granted. Then there's the actual sentence. It's in the actual sentence that the residual amount of time for subsequent things are determined, like parole, and so on.