There are dozens of these offices all around the city. We had heard from a native German friend that you must go to the office closest to your address, but when we were speaking to our attorney, she was sure that we could go to any office in the city. She even called on our behalf and made an appointment - something we had tried to do online, but apparently more appointments are available if you call. The appointments available on the website (at least for the next two weeks) were scarce. After setting our appointment, our attorney chuckled and told us that the office we were headed to was one of the worst for non-German speakers. She printed out the form we would need to fill out and assured us that if we had it completed in advance and pointed at it with a smile, we'd be fine.
Back at home, we sat down to fill out the form, expecting it to be relatively easy despite being in German only. We figured that with today's online translation technology, we'd be able to fill it out without a problem. Four different translation sites later we were cursing our over-confidence and this so-called "advanced technology". In desperation, we started sending messages to all the German speakers we know, but no one was around. Our appointment was only a couple of hours away. I can't believe it, but we didn't even try googling "Anmeldung English" until this moment. Although slightly outdated, we found a helpful site with an annotated version of the Anmeldung form, with comments in English under each box. With this help, we had the form filled out in minutes and were ready to go.
We found our way to the office in Wedding. Walking into the building, we found ourselves in one large room with chairs in the center facing rows of numbered doors on both sides. At the far end, there was another room labelled "Information", and a long queue - we assumed this was for people who did not have an appointment and needed a number (suckers!). Everyone else was sitting on the chairs waiting for their number to pop up on these big scoreboard-like screens indicating which of the clinically identical rooms to disappear into.
Only ten minutes later than our appointed time, we were at last called into room 13. We had brought our German phrasebook and spent our waiting time rehearsing what we would say to the clerk to butter her up and explain why we were there. As soon as our assigned clerk's cold glare caught our eyes, our script crumbled and all we could manage was a badly accented "Guten Tag, sprechen sie Englisch?". Like our attorney predicted, she rolled her eyes and just said "Nein", and raised her eyebrows expectantly and impatiently as if to say "So what do you want???". We fumbled nervously to pull out all of our documents as she waited in annoyance. After that we didn't have to say anything. She typed in all of our information and gave us a stamped certificate (which was free, to our surprise). After 10 minutes we were out of there.
One visa requirement down!