add one

17:49 Jan 7, 2022 

Ça vous donnerait quelque chose du genre: "Rappelez-vous que les dates de début au plus tôt du [cheminement] [diagramme] renvoient à la fin de [cette journée] [ce jour-là]; nous vous recommandons donc de devancer d'un jour cette date du début de sorte à indiquer la date effective du début au plus tôt."

13:28 Jan 7, 2022 

Thank you so much for your contribution

13:02 Jan 7, 2022 

It's about the Gannt charts and about plotting the start and the finish time of each task. Here it is an example of a Gannt chart:
https://www.edrawsoft.com/templates/pdf/develop-new-software...
You'll notice that in case of sequential tasks (not of the simultaneous ones), the starting time of a task is the next day after the end of the previous one.
I think that "add one" refers to this aspect.

11:41 Jan 7, 2022 

To put it another way, your start day is effectively Day Zero, but since we don't count zeros, you have to make Day Zero Day One.

08:18 Jan 7, 2022 

Yes, I see it now: you need to make the actual start date 1 day earlier, as the computer start date is actually at the END of the day stated — so in effect that day does not count in terms of the time available to do the job. So in fact the start date needs to be D-day – 1. It's a bit of a backwards way of looking at it: it really means, 'allow one day extra in your schedule, as the first day is effectively lost' — which if there is a deadline to meet, I suppose that means that the real day when work can start will be one day later than apparently is the case.

08:12 Jan 7, 2022 

It means to allow one extra day in the schedule (or possibly the reverse: to count one day less in the time it will take) — I would say something like: 'augmenter d'un jour le délai...' etc.
It's not obvious to me if they mean 'you can afford to start later' or 'you must allow one day extra'.

08:11 Jan 7, 2022 

J+1