The first step is to approach a DP. You can find the list with addresses on the website of NSDL and CDSL. The DP will ask you to fill up an account opening form. The account opening form must be supported by copies of any one of the approved documents which serve as proof of identity and proof of address as specified by SEBI. Apart from these PAN card has to be shown in original at the time of account opening. This is effective from April 2006. The PAN card is outside your other proof of identity documents and proof residence documents that you are required to submit.
Be very careful about getting all documentation in place. All applicants should carry original documents for verification by an authorized official of the DP, under his signature. The investor has to sign an agreement with DP in a depository prescribed standard format, which gives details of rights and duties of investor and DP. DP should provide the investor with a copy of the agreement and schedule of charges for their future reference. The DP will open the account in the system and give a unique account number, which is also called BO ID (Beneficial Owner Identification number) and used for all future transactions. Your DP account will actually be a combination of the id of your DP and your BO id. It is this combination that you will have to use when you apply for IPOs etc.