It's easy to plan out work for a whole year as all you need to do is drag & drop the task tiles between months or the Unscheduled Work column. Tasks that have been set as either Fixed or Variable will automatically move to their correct sections and can't be moved between the two.
All unscheduled tasks are displayed in the Unscheduled Work column on the right. A task is unscheduled if it does not have a Planned Date. Tasks can be scheduled by dragging and dropping into a month in the planner, which will set the Planned Date to the first day of the month.
The Unscheduled Work column can also be filtered to help you find a particular task. Just use the search bar at the top of the column and enter the name or client of the task you're looking for.
You can also schedule a task by editing it and assigning it a Planned Date.