On your website, you probably installed a template so your content is always formatted the same way and respects some graphic rules. You can do the same thing for a Newsletter so once your own template is created, you will simply add some content in the main area of your template and you're done.
Search Area : this text input allows you to search a template.
Tags : with this input you can display the templates with a particular tag.
Sort by : this one allows you to sort your templates by id, name, sending date, creation date, draft, active, scheduled, sent.
Type : on the left, it will display only the templates with the selected type.
This is the listing of your templates. If you want to delete one template, just hover it and click on delete. To edit a template click on it.