Sales tax practitioner

Hi, i am a b.com graduate and G.D.C & A with 05 years exp. in accounts and taxation field as a Accounatant and 5 Year as a Professional Accountant. I would like to practice as sales tax pracitioner, hence kindly let me know the procedures and formalities for practicing as sales tax practitioner. whether i have to register anywhere else or i have to write any exam. pls anybody guide me in this regards.