Days is a module that allows you to select the days of the week that the school is open. This is important for accurate attendance reporting and is relevant to the Classes module.
To set the days of the week go to Admin > Config > Core Setup > Days and you will then be presented with the screen below.
Tick which days of the week the school is open.
NOTE: Please ignore the sections called 'Curriculum Mapped' and information on Timetables as these options have been withdrawn.