Only one day

Hello.
Thank you and congratulations for your product.
He is clearly very professional and we are really happy.
Now we would like members to only be able to book one day. And not 2.
We installed the restriction, but we can’t find the solution.
When booking on the calendar, the member can only choose one day but that overlaps with the next day.
We searched for a long time without finding anything.
I’m sure it’s possible, but I haven’t found it.
Thanks in advance for your help.