Getting started

The place to begin is to become familiar with the Upgrading Drupal process. The documentation there explains everything you need to know to successfully upgrade a Drupal 6 or Drupal 7 site to Drupal 8 or later.

If you only read one page, it should be Preparing a site for upgrade to Drupal 9, which tells you what you need to do before you execute the upgrade.

Commerce Migrate consists of several modules, each of which is for migrating from a particular source. There are sub modules for Commerce 1, Ubercart 6, Ubercart 7 and samples to help with WooCommerce, Magento, and Shopify. There is also and example module for CSV sources. Enable the module for your source before upgrading.

There are two ways to do the upgrade. One is the via the Drupal user interface and the other is via the command line with Drush.