Clicking a step in the rail opens the first task you have not finished in that step (or the first task once all are done). On a task page the footer offers Back and Next → to move to the previous/next task in the same step, ← All <step> to return to the step's overview, and Done with <step> on the last task. On a step overview the footer shows Back to the previous step and Save & continue (or Finish onboarding on the last step); pressing it records the step as complete and opens the next step, with the message Saved. Opening the next step.... If saving fails you see Could not save your progress. Please try again. Steps saved per kitchen need a kitchen selected first.