I have completed my B.M.S.degree and want to know about goverment customs job exam,pls guide me for the same ...types and where this exam r

Being a management student i want to know what type of exam i have to clear to get goverment custom jobs.........what ,when & which type exam will be conducted for customs job.being a management student which type of exam i have to clear to get job in customs..........pls guide me for the same...