To create a new pattern, call new freesewing.Design(). It takes your pattern configuration, and any plugins you want to load as parameters.

For example, if we were creating a new pattern called Sorcha:

import freesewing from "@freesewing/core";
import plugins from "@freesewing/plugin-bundle";
import config from "../config";

// Create new design
const Sorcha = new freesewing.Design(config, plugins);

This method does not return a Design object. Instead it returns a constructor method for your pattern.

When importing your pattern, it is itself a constructor:

import Sorcha from "@freesewing/sorcha";

// Sorcha is a constructor for your pattern. 
let pattern = new Sorcha();

Constructors are functions you can call with new to create an object. As freesewing.Design() returns a constructor, you can think of it as a super-constructor.