Besides using the “Next” and “Previous” buttons, the user can click directly on the step in order to navigate. At any step the user can navigate only to the immediate next step or any of the already visited steps.

The default WooCommerce validation is performed at the end of the checkout, when clicking the “Place Order” button. You can choose to enable the “step-by-step validation” and inform your customers of any errors before proceeding to the next step.

By default in WooCommerce there is only a login form on the checkout page and for registering the user needs to go to another page. You can choose to put the registration form alongside the login form within the Login step. After registering the customer will be redirected to the next step.