Document how to setup and use the module

Hello

Can you tell me please, which type do I apply this to - Order types, Order item types, or Shipping types?

Also, am I am to add other field types, for example a drop down list, rather than a simple text field?

And the patch that is discussed on https://www.drupal.org/project/commerce_checkout_order_fields/issues/306... → - is this now included in the latest release?

Thanks