You can fork an editable copy of an existing template on the Template page of your blog’s dashboard. You can make changes to a template using the online editor, or you can edit the template’s source files locally from your blog’s folder.
After you have browsed the developer documentation, consider forking a copy of one of Blot’s templates and reading its source code.
TIP: You can inspect the JSON data used to render a template if you append the query string ?debug=true to any URL on your blog.