You can manage opportunity tasks in the Task section. Tasks are associated with stages in your pipeline.
Update Tasks
You can update status, due dates, and assignees by interacting with the task.
Subtasks
You can add subtasks by clicking on a Task name and clicking the Add Subtask button.
Task Templates
Once you’ve set up your tasks, as an Admin you can create a Task Template by clicking the “Save Task Template” button at the bottom of the task list. Going forward, new opportunities will automatically have the same tasks created and associated with each stage.