Only open visits are filled
Auto-build looks at the visits still to come that need a carer, on the branches and days you choose. Every carer you have already placed stays where they are, so it never undoes your work.
It picks carers who are in the visit's branch, available at that time, free of other visits and able to get there in time.

See the result before you confirm
The preview lists every carer it would put on and the drive to each visit. Nothing changes until you confirm.
When you do, the carers go on as a draft. Staff won't see them until you publish the week.

Clear reasons when nobody fits
A visit it can't fill says why in plain words: nobody in its branch is free, everyone free is on another visit, everyone free would arrive late from their visit before, everyone free would go over their hours, or the visit needs two carers and not enough are free.
Those reasons tell you what to change, whether that is asking someone from another branch or moving a visit time.

Questions
Will auto-build move carers I've already booked?
No. It only fills visits that still need a carer. Everyone already on the rota stays put.
Can I check it before it changes the rota?
Yes. It shows a preview of every carer it would put on, and nothing changes until you confirm.
What happens to visits it can't fill?
They stay open, each with a reason, so you can sort them out by hand.
See Isabelle with your own rota.
We'll walk you through it.