Step 1: To create a new survey using One Question at a Time, simply select Survey when choosing your data collection method. This will automatically format your survey to display only one question at a time.
Step 2: For existing forms and surveys, you can toggle this setting on via Form Extras within the Build tab.
Step 3: Once turned on, you can format your welcome and submission screens by clicking Settings followed by the Welcome & Submission Messages tab.
For additional information, check out this help article.