GSTR 3

you can have full article from the link provided below

/articles/gst-returns-3-3b-story--30836.asp

Go to Gst website... login in with ur credentials... go to returns dashboard... click on GSTR 3B ... fill the relevant fields like ur turnover fr the month ( taxed... zero rated... nil applicable ) in fr ur business activity... u will c a lot of other sections u can gt d descripttion of the same by positioning d cursor on them ... fill d input credit fields for any purchases made in July... after feeding the above data .... create a challan and make d payment by selecting ur preferred mode of payment... once d said payment is reflected in cash ledger ... go ahead with submission and filing.
Best of luck

See video on below link for clariifcation

https://www.gst.gov.in/help/helpmodules/