One important aspect when making the project plan is to set the working days and working hours. That is done in the Calendar & working hours window.
Opening the window
Navigate to More..>Customize project..., and then choose "Calendar" to the left.
The window is split up in three parts: Holidays and observances, Week working days and working hours and Settings for specific days.
In the Holidays and observances part of the window, you select the country which most closely matches your local holidays and observances. Holidays of that country will be marked red in the calendar, and will also be shown in the To do list, and in Project Overview.
In the Week working days and working hours you set the week's general working days as well as the general working hours for the week. Free days are marked gray in the Calendar and are also shown in the To do list and in Portfolio find.
In Settings for specific days you determine any special settings for a day that should overrule the general settings made in the Week working days and working hours part of the window. The days you have changed will be marked green for a free day/working day change, and red for a change in working hours (in this calendar window only).
Note: The calendar setting applies to the whole project.
An example using the calendar settings for the Japan within a project (holidays are denoted by red bars):
Changing working hours in a project changes the allocation (in hours, not percentage) of the users that have assigned tasks in that project.
If we have set a six-hour working day, and allocate the user to a capacity of 50% in this project, this would indicate that the user has to work three hours a day on this task. An eight-hour working day with a 50% allocation would indicate four hours of work on this task per day.