Who could tell me what should the newcomer of learning Japanese do?

I would say when beginning learn some basic phrases, but focus on reading and character recognition in regards to Hiragana and Katakana. Learning those first will get you more practice in reading at a comfortable level and won't leave you relying on Romaji, which is a bad habit when learning. Pronunciation is also important, and you should make sure you are pronouncing the vowels correctly. Read, write, and speak until you are comfortable with it. ^^

I agree with Mytch 100%!

Thank you =)