You can specify how many tasks must be completed before a checklist can be marked as completed by setting the Task requirement property on a template. There are two supported properties, Any task and All tasks.
Any task is the default and allows a checklist to be marked as completed with zero or more tasks completed.
All tasks requires every task in a checklist to be completed before a checklist can be marked as completed.
To set task completion requirement you open the template and click on Set task properties in the action menu.
This will display the two possible task requirement properties, where the currently used is marked as selected with a blue icon. To change task requirement click on the property currently not marked as selected.