1. Select the "Configuration" option from the menu.
2. In the "Preferences" section:
a) enable the "Select if you want to configure booking restrictions" option;
b) check the "Maximum length of stay" option;
c) and save settings.
3. In the "Set prices" window:
a) select a date;
b) enter the requested number of days;
c) set for which days you want to activate this restriction;
d) and save settings.
Related articles:
How to set the minimum booking length for selected days?
How do restrictions work?
How to set (enable) the restrictions?