The word "template" is a good choice. "Once you make that sequence you have defined the 'template' for the list." Many software applications include built-in templates or allow users to create their own. Templates may prescribe layout, color, fonts, and other attributes to implement a particular look-and-feel. The user can created a new document using a template as a starting point and then focus on populating the document with their data, without worrying about the format which the template provides.
"Schema" may be the word you're looking for, given the context of your example. For example, a database schema or XML schema defines data types, structure, and relationships. e.g Schema in the more general sense means "a method for making, doing, or accomplishing something." https://encyclopedia2.thefreedictionary.com/Schema+(database)https://www.freethesaurus.com/Database+schema