I've studied Arabic for 5+ years now. Firstly, forget everything you know about any other language because it won't help you. To get started learning the alphabet, here's a good video that shows both how the letters sound and how they fit together and how they look in different positions in words
Grammar is a whole different ball game. The purest form of the language is the Quran and it will have the end voweling for the 3 grammatical cases (nounal, accusative, jussive). Sentence structure is almost always Verb - Subject - Object. To build vocabulary, start with the 3 letter root and apply it to the 10 different verb forms in this chart http://arabic.desert-sky.net/g_vforms.html To build listening, BBC Arabic has news clips with attached vocab.
This is as close to a crash course as I can give you over the internet while I'm at brunch but I hope it helps a bit!