Writing answer

Hi sir ,
In one question say flowers anytime from 2002 ,i undrstood the system , in that in revision kit the answer for me it feels bit complicated …so is it necessary to practice the question and answer as it is or i can have my own approach in writing the answer ? Is if possible in this question to answer the sales system by writing the answer from ot notes given in chapter some accounting systems with some explanation .
Hope you understood my question