1, confident and generous, don't be nervous.
2. Yes, submit the certification materials to the visa officer.
Make sure that your visa application form is filled in correctly. Many times, the questions asked by the visa officer are based on your personal information on the form. Please pay attention to this.
You have been refused an American visa once, so you must not be careless when you re-sign. You can read this article, which is good for you to re-sign. It's not terrible to be refused a visa in the United States. What's terrible is that you don't even know these things after being refused a visa! 》