If a user asks “How do I ______” to your agent, you should offer examples of how they can do the task.
The first takeaway is that you must be prepared to field the question “How do I do (bot’s main functionality)?” question inside the bot itself.
The second takeaway is that by providing examples, you will help the user formulate their own questions/messages. Once again, it helps if you are not too literal.
Specific to API.AI, look at your intents and see if there are any user says examples which start with “How do I” or some similar phrase. If there is, take a look at how your text response. Do you give an example? Is the example clear and brief?