Thank you very much for your comment and your advices! For your nickname I can guess you like Moszkowski, don't you? LOL!
This was my way of practising it:
First, I played it as perfect as I could (as a concert playing) and after one playing I began to study the piece. I played it very slow (around 60 bpm) left hand alone, very slow right hand alone and later both hands togethers. Later, I played it faster (around 80bpm) in the same procedure [left hand , right hand and both hands] And that was the way I learnt it

As to the dynamics, I really was surprised when I began to play that piano. It sounds really low when you are playing it, but when you are listening to it it sounds totally different, so I was a little confused, what misled me a little bit

Thanks!
