When I got a work permit when I was working in Germany, I went to the Arbeitsamt and applied for one. My employer was involved as well, calling up the Arbeitsamt and pressuring them to get it through. The Arbeitsamt lost my application twice, and I believe that after the first time it was lost, my employer applied again on my behalf. All in all, it took about 1.5 months to finally get the thing. The whole experience was quite frustrating, and the Arbeitsamt seemed to me to be pretty unhelpful and apathetic. Fortunately, my employer provided me a lot of support through the entire ordeal.

If I recall correctly, I had to provide documentation showing that I had a job offer. I don't remember exactly what went on: this was about 5 years ago. I'm pretty sure that the Arbeitsamt will contact the company offering you the job as well.

In any case, it won't hurt to go to the nearest Arbeitsamt and see what kind of things you need. You, however, are probably not in Germany at the moment, so you may have to write to the Arbeitsamt or contact the nearest German consulate. It certainly doesn't hurt to ask!