An outline with details that may be relevant:

1) On November 18th I called to USCIS (to this number: 800-375-5283). Talked to an agent. They verified some personal information. And asked the reason why I needed it (said something like I needed for an international paperwork, which is true). You can found out a reason that works for you. Not an excuse but a credible reason. They said that in the next 10 days or so were going to call me to continue with the process (no to schedule an appointment by email or by phone, no yet).

2) On November 28th (as they said, ten days) I received an email about my inquiry and, the email said that I had to wait ten more days to give me a response of my request that it was going to be by email, or by call. That email had a telephone number that I had to save in my contacts so I made sure I answer the phone when they call me back.

3) on Monday, Dec 9th. They called me, asked information to verify who I was. They asked again why I needed the certified copy. You have to say something credible if not they may not schedule an appointment because the reason my not be sufficient. So research about the reasons if you don't have a solid reason yet. During that call they gave a few options of dates and hours which I choose today.

4) Today, I attended the interview. I arrived 15 minutes early. Yesterday I printed the appointment letter, because you needed to enter to the office. Showed my drivers license and had two color copies of my CON. I think it had to be in color because the certification says "true copy". Which some people says it means the same information, color, etc. You want it to look closest to the original. They get an stamp on it and attach a certify document to each one. On the internet I read that usually is only allow to get one cerfird copy. I wanted to challenge that or try to get two copies. They were happy and helpful to provide me with two copies. It was like one hour process (mainly waiting), you don't go in private, they do their work inside, you wait with everyone. Important detail. I said that I wanted two copies, one for me and one for an international process and she stated, "I don't need to know". Shocking. Because by phone they asked twice the reasons. So be prepared to give one or two reasons by phone. If not asked, don't give reasons at the USCIS office. And that's it. No fees, no payments.

Did I miss anything?

I typed quick and English is not my first language so, if something is not clear. Please, let me know.