Getting registered is one thing.  But if you have not been in this business before, the best thing to do is to get a job at an established tax practice or accounting firm, ideally to shadow a knowledgeable mentor.  You will need probably 3 years to learn the ropes and for the light bulb to go off.  You should expect then to take more years to fully develop your expertise.  It would be different if all you want to do is to prepare basic tax returns.