The Scheduler allows you to define Sub-Tasks within Scheduled Issue, which will be created together with the newly created issue. This option is avaliable only when Sub-Tasks are avaliable within JIRA instance.
You can add new subtask to Scheduled Issue from it's details page, by clicking:
- More -> Add Sub-Task
- Or the "+" icon above the Subtasks table
When you will choose one of the links, the following page will appear:
You can enter Sub-Task field values here. By choosing Save button, Sub-Task will apear in the Sub-Tasks table: