Dear Raj,
The principal employer needs to be registered under The Contract Labour (Regulation & Abolition) Act, 1970. The procedure for registration is to have the agreement copies of your company with the contractor(s) along with the prescribed fees which you can very well inquire about in the Labour office to find out the exact fees.
As for security services, based on my experience of having worked in Maharashtra, there is a regulating body by the name of Security Guard Board under which the principal employer needs to get registered. If there is any such body existing in Bihar, please find out. The process of registration is the same.
Regards,
Amit