Tasks as main element
Task is a main component of the plan. Plan is usually composed of dozens to hundreds even thousands tasks.
Tasks can represent a single activity (lock a door, make a phone call, press a button or run a script) or a long term process (hire a person, pass an exam or lease a building) depending on granularity of planning.
Task is mainly defined by its name, description, accountable person (Executor), relation to other tasks (grouping or precedessors) and timing.
TaskControl user can freely place tasks in the plan and group them with no relation to their relationships, executors, content or timing.
Usual approach to tasks structuring correspond to type of a plan as described in best-practices.