There is of course the possibility to change the timetable manually. This is done directly in the timetable windows, either in individual timetables or in overview timetables.
The Getting Started Placing periods can be found here.
The Getting Started Shifting periods can be found here.
The Getting Started Swapping periods can be found here.
The Getting Started Unscheduling periods can be found here.
The Getting Started Assigning rooms can be found here.