Tap the task icon to get to your task list.

Then tap the (+) icon at the bottom right to create a new task.  

In the task editor that appears, tap the menu bars at the top right of this area and choose 'convert to checklist'.

Checklists can only sync when they are assigned to informant sync. If you choose to sync your checklist with toodledo or google task, they will be converted to task/subtasks in those services.