They say they don't speak English but I just have to wonder if employees at the immigration office would have been hired if they did not have foreign language skills. For Example, My husbands first appointment the agent shook her head "no" that she did not speak English. Two weeks later at the second appointment with the extra paper that we had been missing, She was speaking English very well to the person in front of us.
You do NOT need an attorney or anyone else to go with you. If you have a friend who speaks Portuguese, they would be just as helpful but really, I did not speak Portuguese and I did fine. You have a list of all the required documents. Take those and every other piece of paper you have relating to your move here. Take a box if you need to. But keep the required documents separate. When your number is called, put all those documents on the counter. They will look at them, they will scan them in the computer, they will have you stand & put your fingertips on the big machine that also takes your picture. The paper that you are given to fill out with your mailing address, make sure the address is correct. Your card will be mailed to you.