I was just there for my cartao do cidadao. You do not make an appointment for cartao do cidadao or passport. You need to go as early as you can and put yourself on the list. Yes , plan on being there for at least a couple hours or longer. My last visit they closed the doors st 10 AM because of to many people. Another crazy day at the consulate...there is no one to contact for info anymore so read website for what you need to bring with you so you are prepared and not turned away. Good luck!
You should get on the website and book yourself an appointment. If you have your Portuguese birth certificate it should be easy enough to get double citizenship. The website also notes documents needed.
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