TL;DR
A useful task says what to do, for which class and by when.
Before you begin
Open your own planner and use the add-task action.
Key points
Write a short action-based title and add instructions in the notes.
Choose the correct class, task type and workload.
Set the due date and, when useful, an announcement date.
Save, then schedule a work session; creating the task alone does not reserve time for it.
Related help