@Johnny303
So you do no want guests checking-in/-out during the specific month and at least stay for that whole month.
It means you need to create a ruleset which makes it only possible to make a booking just before the month starts and ends after the month has finished. Setup also depends on how many nights you want to be that time periods before/after the month.
If you create a ruleset which says minimum stay is amount of nights in the specific month and limit it to minimum of 1 check-in day (which offcourse must not be the first day of that month), then nobody can book during that month if the ruleset is applied.
In the week before that month you need to set minimum stay at least to a value the booking will include the upcoming month, also set a maximum stay to be sure booking will not be to long after the month has ended. And you can use limitation of check-in/check-out days also, if desired.