To use task automation first you need to setup task templates and assign them to workflow as stage automation in order to execute.
Create and manage task templates
For tasks to automatically be set when deal is created and moved between stages you must make templates and automate them. This will automatically create key tasks for each deal, each user and each stage - to keep you on track.
To set Task templates go to Settings > Tasks (in template section). Click "+Add new", write template name and description, then add sub-tasks if needed. Press “Save” when done.
Detailed explanation on task templates can be found in our Task Templates article.
Create tasks automatically as workflow automation
Go to Settings > Workflows. Edit or create a workflow where you would like to automate your task templates.
Click on the orange "Automate" button under the stage where task template should apply and pick the task template to load it into that stage automation.
In the following popup window will show, you can fully customize template:
enter task name
choose default assignee of task (specific user or deal owner)
insert comments
add sub tasks if needed.
set the due date and interval
Confirm with “Save” button when done.