To set up an automatic email, you'll first want to align that with a workflow stage. To do this, select: Settings>>Recruiting Workflows>>Select a stage>>Configure Rules for this stage
Next, you'll want to check the box for Send an email message. After that is checked, you may create a new template for this workflow. Please note, these templates exist ONLY within your workflows and are separate from your 'my templates' section. The templates you'd like to use must be created within this section using the plus sign depicted below.