Service tax return procedure

Dear Freinds

abc pvt ltd company can obtain a contarct from bhusan steel ltd. for Rs. 4100000.00 on oct -12 & the bhusan steel paid the bill amount through part basis & the final bill payment received by april - 13 & abc ltd company paid the service tax amt Rs. 506760.00, and my query is what is the procedure to file service tax return for f.y. 2012-13 & 2013-14