Dear Modi
If you have to engage the contract labour, then you must register your organisation / factory as an Establishment under Contract Labour Act, for which you have to use Form I. Alongwith the Form I you must submit a list of contractors you are planned to engage. Whoever contractors name you have submitted while obtaining the registration certificate for them only you can issue Form V. If you want to engage a new contractor, then you have to submit for additional list of contractors, whose Name to be added on the Register of Contractors, which is maintained at Labour Commissioner's Office.
As per central Act if the workmen strength is less than 20 then, the contractor is not required to obtain the license, but for state, it differs from one state to other. So you will have to refer the state rules to get the correct information.