which process to apply to file gst

Post application for GST, I got my GSTIN No in July'2017 from the govt. I am a Sole propreitor of a Manpower Services firm. In July 2017 I billed my Client for providing Manpower Services. The Inovoice raised and presented to the Client from my side, for Services rendered to him were as follows. SERVICE FEE Rs 100 IGST @9% Rs 9 SGST @9% Rs 9 Total Invoice Amt Rs 118 In August 2017, my Client had paid me a Cheque of Rs 108/- ( Rs 118 - Rs 10(10% TDS on Service Fees of Rs 100) ) On 3rd March 2018 I have now prepared a Challan in GST Portal and deposited Rs 18/- in GST account, for wich I have got the Challan Receipt. Till Date I have not filled any GST forms or ITR forms as I have no Knowlede about the process. I therefore request you to clarify and guide me on my following queries. My Question is as follows. 1. Which GST FORMS do I have to fill ? Kindly tell me the order in which I have to fill them. 2. In which form and which Section or column do I Show the Rs 18 which the Client has paid me( the GST amount). Please recall as stated above that this Rs 18 received by me from my Client was deposited my me through a Challan created on the GST Portal in March 2018 and was deposited in the GST account through my bank using NEFT. 3. How do I Claim for TDS returns. Your reply and help will be highly appreciated. regards Franklin