it helps in all languages, but the problem is that there are too many dialects, so if you want to learn Standard arabic it would help but not that much, maybe you should watch some cartoons or historical dramas, because they would be in standard arabic, :) and to the question: what if you don't understand everything ? I would not worry about that because it's also good to just get used to the melody of the language and after a while you might be able to understand some words through the context hope I could help good luck

No , you can't learn a language only by watching movies or / and listening to music . you have to learn alphabets , pronounciation , grammar , vocabulary .. this is necessary for learning any language . Tv or music will help only .

yes it will help a lot, plus regular classes with native to understand the structure of the language, lots of luck

Yes actually it's the best way, but You must know at least the basics of the language. Good luck

I don't undrestand your question. Please put it in a different form.