Your question is not clear.
I presume, you want one of the following :
(a) For the labourers engaged through contractor, you need not prepare any salary statement etc. for them. You have to pay to the contractor as per your agreement with him and you should check, whether he is following the labor laws.
(b) For the employees on contract basis, you have to pay them on production of bills by them, as per the terms stated in the agreement