The calendar view from the top menu allows a number of differing views, dependant on what you would like to achieve for example:-
By devices - Allows a view of the tasks by date.
It could be that we want to make sure we combine tasks by a device, for example we have 2 tasks with differing maintance periods, but the is just one day apart, one on the 1st and one on the 2nd - I can right click and change the date of the one on the 2nd to the 1st so all maintance is done on one visit.
The day, week and month views can show date ranges, for selected performers, where we can see the tasks, the status and we can also use drag and drop to schedule the tasks.
The blue on the 20th is a public holiday, which is easy to see when these are setup within Alldevice.
For the day week month you can also setup the views to display the working day range, combine performers ie one date column, vs each performer and the dates and for weekly and monthly views to hide the weekends.
The views allow for scheduling changes by devices, or person to make the taks of managing holidays, sickness or managing workload etc. simple and easy for a manager to update.