grand prix attack

how does white should continue?

this question needs a deep analysis.

First and foremost you lost a tempo in move 8 by taking the knight. It opened up the b file for black's rook. Giving away that pawn weakens your queenside decisively as well as the a1-h9 diagonal. The pawn sac was premature as black's camp is still very solid. In the final position, black has the upper hand already. Losing the c2 pawn would be too much. White can't make direct threats as all plans can be defended easilly. The idea of Qe1-h4 is very comon here. What is lacking is playing Kh1 to avoid some nasty checks on g1-a7 diagonal. Yo could trick your opponent though with 13. exf5 Bxf5 14. Ne4 Bxe4 15. fxe4 opening the f-file to add pressure on the f6 knight. But after the cold blooded 15...Re8 with the idea of defending the knight via e6 stops all hopes for white in the endgame.

My Advise for you: It is good to play like the great attackers & tacticians. But you should play it in the right time. 

this system is advised to play by gm roman, so i believe that this is the right way to play, but there is something in my mind that i realy dont know and that is how white will continue...

i take the knignt on move 8 to prevent it from going to d4 square and to prepare an attack

White's play looks very reasonable to me up until 9Qe1 Rb8. After that can decide if want to go all out for attack, maybe something with e5 better?, or play b3 at some point. Black's queenside weaknesses won't run away. As black would prefer 5...Nd4 to 5....d6.